I would start your first project out of muslin. Its fairly inexpensive and easy to work with. Don't waste expensive fabric teaching yourself to sew. Start out with an easy sew pattern just so you can get the hang of it down.
With the tissue pattern there will be an instruction sheet. It will tell you which pieces to cut out for what item you will be sewing. Once you do that there will be a diagram of how you pin it to your fabric, where the fold should be, etc. The shaded pieces you see in the diagram are the "wrong side" of the pattern. Cut the pieces out the way it shoes you on the sheet. After you have all your pieces cut out, follow the directions on the insert for the item you are sewing.
If you try drafting the coat in muslin, make sure you make an allowance for the bulk of the fabric of you will make the jacket too tight. When you get the right fit down you can rip the seams and use the pieces of muslin as a guide for drawing your coat pattern. But I would start out with something like an aline dress or something else simple until you get the hang of adjusting patterns to size. If you have any questions feel free to convo me
Good luck and happy sewing :-)