HELP NEWBIE WHO BOUGHT BROTHER BES 1210AC

Oh wow...... This is going to be a big learning curve then.
Being familure with screenprinting and plotter cutters doesn't really help... well it might a little but not really. Screenprinting you use "rip" software ect... But with embroidery the setup is for someone to literally redraw stitches in software.

Embroidery requires digitizing or punching (oldschool terms to refer to redrawing using embroidery techniqes) into a specific file format. Which is the processes of redrawing and programming a stitch file to lay stitches down.... you used the word "convert"... which really means your in early stages...

"converting" is what is known as auto-digitizing... and while it exsists it doesn't work like rip software it is more of a program tool like auto tracing a low res bitmap into vector art. The results are aweful and can sometimes damage the machines. Auto-digitizing is for shortcuting parts of artwork but needs a skilled digitizer to correct the parts.
For a newbie the best option is to get in contact with good digitizers and pay for them to digitize... that said do not go with the cheapest... the results are bad. Also

The top 2 softwares are Wilcom and Pulse.
The software is usually between $2000 for low tier and home versions. And $12,000-$15,000 for top tier.

Taking it on yourself is... not only costly but one of the hardest things to get good at from artistic and technical perspective.

Because you have a brother (old and I know a lot about them) and only a single head... If your seriously going into embroidery you would need more than a single head as it is really only useful for a handful of things (IE orders of 4-6 or doing specialty work when pairing it with a multihead)
The learning curve is going to be even harder. You need backing materials ect.

Part1.
Err the screens on newer machines just display files loaded into the machine and their progress and HOW the file is aligned to the machine (lets you know if you have the artwork upsidedown when you need to rotate it) and have a lot more control. Industrial models don't have (or dont have much) built in software for creating art. Its a verification and progress tool. At least all the industrial models. The machines themselves can have internal memory storage so you can load files without having to go to a computer but they don't design new art.
Some home models have built in files and tools but they don't have the ability to actually create artwork new except for preinstalled text fonts but that is about it. All new files are made using digitizing software that can on newer machines be sent directly to it.

Its not so much the workhorse factor but more in line of what is your business model, what you are using it for? what kind of work will you be selling with it? How much work do you plan to sell? How will you charge for it. That determines if it is a profitable return on investment or not... Do you have a storefront/warehouse or is it out of home? (genuinely asking cause it could be a bigger investment than you think thats why single heads are always up for sale)

I have a brother 1201 and 1204. The 1210 and 1201 model heads just cannot produce the same stitch quality of the 1204 and the 1204 cant hold a candle to todays modern machines. The speed hasn't increased at all really in the past 20 years its the overall quality and accuracy. And yes All embroidery needs some kind of backing but not all backing is equal or correct.

The point i was trying to make was more a single head is... a useful tool but not the most profitable place to start with. And don't take what I am saying the wrong way. Its more a forewarning of not making the costly mistakes that we/I had made in the past. I am an expert because I made mistakes and worked my *** off to fix them/get better but it takes years.

Depending on the digitizer yes and no. Most of the time you give them the file in the format of their choosing and then if they are good digitizer they will want to know what kind of fabric it is going on, the size, if you need a hat file or just a standard left chest file. (you need seporate files for both). They will also warn you of limitations within the art that some art can't be that small or some art needs to be adjusted (which they will do on their end but they will warn you)....

Part 2. Software files and how the machines work.
Wilcom and Pulse are the top two producers of Embroidery software (with a few dozen other companies but honestly its best to avoid them if your really looking to expand in the future... because ALLL embroidery software files are pretty much proprietary and generally can't be converted... or not well. (quality loss) So if you upgrade to a software from a different company all your previous files would not open in it. (exceptions to the rule but generally the case)

Digitizing & Embroidery machine files.
To start with there are 2 types of embroidery file. The Outline file, and the Machine File.

Outline files are basically a form of special vector file and actually creating embroidery files starts out very similarly to drawing vector art from scratch but from from that point they differ and it becomes less about the software and more about the skill level of the digitizer to predict how the fabric is going to move and create compensation without reducing quality. Ouline files are usually proprietary files that only open up in the same program they were created in. These files are also what you need in order to improve quality resize edit and most importantly used to improve run times.

The second File type. Machine file. For brother you need .dst which is the standard file type almost all industrial machines can read but others do exsist but are generally related to a specific brand of machine. in the case of .dst all outlines and color data are stripped out and the final calculation of the xy of each individual stitch is created. Oddly enough its not a coordinate map as much as it is values for movement that refrences the previous coordinate. These files are what are needed to run the machine at a basic level. These files are usually something you never want to edit or mess with but it is possible to edit them but you loose quality along the way.

While I absolutely think everyone should have the good software I don't advise people to buy it until they have a year or two of embroidery under their belt. Cause learning to run the machine is really really easy. Digitizing a file that runs perfectly looks clean doesn't break the machine, and doesn't take 4x as long to produce than it should... that is hard.

sounds like you're on you way to a plan. as far as software goes, its probably best to start out with at least a lettering/editing package. they're less expensive, and if you get, say, Wilcom basic software, the digitizer should be able to send you the .emb file and you can easily resize and manipulate it. i believe wilcom is probably the most common software now so it should be easy to find a digitizer that uses it. if you do decide to get into digitizing later on, you should be able to upgrade it to the full digitizing software. but, honestly, it sounds like you have a lot on your plate and you may never find the time to seriously get into digitizing. i have some customers that have been doing embroidery for over 20 years and still only do basic lettering and simple designs, and send the rest out. when you have your customer pay for the 'set-up' (digitizing), it shouldn't cost you anything to have it done. there is no substitute for a well-digitized design. especially starting out, because if you're having trouble stitching a file, you'll wonder if its the machine or a problem with the digitizing and you'll pull your hair out trying to get a decent sewout. the digitizing makes ALL the difference between quality and crap, and customers coming back....or not.

A minimum of 12 pieces, average 8000 stitchcount 8 trims/color changes) estimated averaged out time for you would be 10 minutes machine prep and material prep (cannot use the word setup cause that is what the industry calls digitizing). A single item would take approximately 15 minutes per run/swapout to the next set. meaning a set of 12 items would take you over 3 hrs. +/- Not including cutting off backing, trimming loose looped and stray threads and steaming hoopmarks out. which means assuming an average overhead cost of production plus profit margins you would have to price it at $18-$33ish to make any money while a competitor with a 4head, the same overhead costs and profit margins can price it at $6-9 per piece for the work. Single heads are more profitable when your selling an item that cost you $25, has a retail price of $50 and are charging $15 to put a name on it. or more often its better for doing 1 full back item while you are running a 4 head (the real profit machine). Or lastly modern single heads are generally designed for personalization automation where you are doing 20 items with names and have 4 single heads auto loading name files.
My suggestion is if your seriously wanting to add embroidery... starting with a single head is not how you do it. Single heads are not for mass production they are for specialized tasks, prototyping and, and small qty orders to be handled at the same time someone is running a big machine. Meaning if your serious find a way to finance a used multihead cause those things can be cheaper than a brand new single head. (12-20K for a new single head) or rethink your business model to take better advantage of its uses IE high profit margin products where you only really need 1 or 2.

People who are use to comparing screen-printing prices (especially retail) look at a full back or left chest price for embroidery and scoff and call you a rip off artist even when you have multi-head machines. But if your selling a single $150 retail price backpack with a logo that takes 15minutes to run... suddenly your making genuine profit and people don't freak out as much cause they respect the price of the item but not of the work.

You also used the word patch... Doing a logo on a piece of apparel is just considered Embroidered apparel. where as a patch is a slightly different process where you embroider onto a separate material and attach it to the garment. Doing all in house is extremely labor intensive compared to direct embroidered garments. Where as full patch making... requires a minimum of 3x4heads 2xsingle-heads, All with sash-frame flatbed attachments and powerful software or massive understanding of the machine. A single piece of fabric and backing is attached in a square and the patches are nested onto the fabric, A laser or flatbed cutter with a cut file matching the material, and a single marrowing machine (professional patch edger). 2-3 people could run that many machines efficiently reducing the price and costs of labor... reducing overhead costs and efficiently funneling the workflow.

As for your questions.

A. Easy and Good are mostly mutually separate. But if you are looking for failure and good than If you really want to pay money for something easy to use... My suggestion would be purchase wilcom lettering studio. It can create text via built in text fonts and adjust and edit a files stitch length, pull compensation, density, unerlay and angle of the EMB outline stitchfiles from a digitizer, it cannot create new objects other than text but it has powerful edit controls. usually retails for $12-15hundred. That would be my suggestion for starting point especially because wilcom does great trade in and upgrade deals allowing you to buy as you go without sacrificeing your file history (often times worth more than the software do to replication and recreation costs).

B. Digitdana here. I have not used them because I do my own digitizing but as a note the ROI is only cause I understood things by the point I bought the software 2.5 years ago I am still paying off debt for the first 2.5 years I didn't understand things... get in touch with them and they can guide you on the outsource digitizing process, and they will give you an .emb and .dst format (wilcom also offers a free tool that allows you to open raw emb outline files and make sizing, and other changes then convert to dst for the machine but don't resize more than 10% cause high detail art requires use of tools that cannot resize properly... IE manual stitch control instead of vector control.

C. A dst saves artwork with a few major control types. Penetration (stitches), Jumps (moving to a position but not creating a stitch), Trim (which in dst format is 3x 0.0 movement jumps) and lastly Color changes.
when you load a dst file into the machine you then have to do a needle select... and when the file needs to switch to a new color you define which machine needle has that color. and the reason you need to do it that way is because you can create layering effects in complex artwork for instance You need the program to go from black to white to black to create a layering effect you need adjustment. you also have instances where your running the same file on 20 things but you have half using an outline color of one color and the other half using a different color while the rest of the file remains the same. it allows you to change needles for color associated objects midway though without loading new files.

As a note trims and color changes are extreamly costly. the average time for a color change or trim on your brother single head is approximately 10-20 seconds., where stitch running rates are approximately averaged out to 750 if your running above 750 stitches per minute if its running at a good control speed and adjustment speed... The internal control settings if you have it set to high ish quality the math balances out to 1 trim is worth 250 stitches. An average file can have anywhere from 5 to 15 trims... 15 trims per file easily brings the run time up by almost 4 minutes on average. 4 minutes per run/ running 12 piece minimum is 48 minutes of total increased production time. Low quality software does not allow for improved trim control as such will cost you LOTS of production time and high quality software would be prohibitive on ROI on a single head.

D. The hat driver setup time on that... yeah there is no "improving" its swap out time there is only mastering it through practice... thats why most have swapped out to a 4 position and 5 position mount instead of 8.
And you would probably be looking at a maximum of 15-20 a day or less in terms of output...

Lastly... Oh dear... you bought that POS for $2400.... I mean... If the previous owner knew what they were doing with it kept it maintained and could prove it worked... you bought an unknown... Brother Industrial machines are presently worthless without expertise training and proof behind them. That model is so old and Brother has a poor quality compared to cost reputation... And later in their life an even poorer quality and reliability to cost reputation... its... bad.

Lets put it this way if you want to genuinely start embroidery that is an undertaking but not one to take on cheap or lightly... Many embroidery companies go out of business without the right understanding in investment... invest to low and you'll never be able to sell enough... invest to much and without the knowledge you're ROI is litterally... 6years of work trial and error debt mistakes ect if you dont invest the right way.

single head focused embroider businesses have a general thing in common. they are selling premade artwork with minor alterations and maybe stock personalization at a high premium... Usually tourist type environment where people will pay a ridiculous amount...

This is not to be discouragement I am trying at least to give genuinely cost analysis on this topic... as this industry is a mixed bag of people quoting numbers without knowing what they are doing.