This is an instruct-able on making a backpack.
Step 1: Cutting out the pieces.
First you are going to want to cut you pieces. I cut two to 10 and a half by 15 and a half those will be the front and back panels. The bottom I cut to 10 and a half by 5. The sides are 15 and a half long and 4 inches wide you will want 2 and 4 15 and a half by 2 and a half for the straps. In the picture I tried to piece them all together.