question

hello designers..
Attached pic is a scaned image of a shirt that customer of mine ordered me to make a prepress designing (exact copy of it) - (the file and the filmoutput) for the following silckscreening process.
As I am still very new into this recently, (thats my first job actualy :) I want to ask some of you, who can let me know of how effectivly to proceed. Step by step would be just better..
I will have to use Corel (as thats what i am a litttle familiar with) or a soft that someone could sugest me to use for vectorization.
If some other method (not a vectorization one), just explane to me pls.
My asking is concerning this special case. This is exact order and I will wish to have exact helping answers. The whole design is about one only color of printing. Not any shadows - its solid. These parts up there of the scanned image ( parts of some embroidery) is not to be done. These vertical lines are from the background (means to be ignored)

Please only profesionals to give help.
Its my new step into a field of textile printing and just want to get the essential info if possible. Thanks a lot in advance!
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for those that want to open my files let me explane:
these files are partial RAR files (for being extracted) and all 3 of them contain just one JPG graphic inside.
To proceed after download you must RENAME each one of the files with erasing final 4 simbols if their names. Then all of their names will look like "...part1.rar" "..part2.rar" and "..part3.rar"
Why they seems as a Word files? Well, they are not actualy such DOC files. I did this because of limitation of file types acceptance during we attach files into our posts here.