First time ever sewing a jeans. Learn a lot. You can download the file here. The pdf is for projector, not printing.
I use this new cheap fabric I bought instead of muslin. It is two times cheaper than muslin, which is good so that I don't feel restrain to waste fabric. I cost about 40$ for 63" x 40 yard. The main downside is the fabric kind of melt a bit when ironed. The vendor actually sells it as fabric to wrap dead people for burial.