first cut out a section that you want to use, i used the section with the back pockets, both of them. if you want your purse wider than your orginal cut, measure the piece that you cut, adding seam allowances, width and hieght.
next, sew in your zipper, then your lining, turn right side out, i used the waist band off of the same pair of jeans, remove waistband, measure the width of your purse, fold waistband in half, if your purse is 10", cut at 51/2"; to make the top band around the purse, using the buttonhole and the button for front decoration, looks like someone forgot to button their pants, i also used the remaining waistband for the shoulder strap.
now, i cut off the belt loops, i put two on each side, total of 4, where the straps were attached, added 3 more in the back, one in the center and the other two on each side of that, i also, put two beltloops in the front. now, i had an old leather belt that i cut off, punched a new hole in it, and looped it through my belt loops.