Unfortunately this post does NOT include measurements. I have lost my plan, but as soon as I find it I will post it.
Stuff you need: fabric; plan including measurements; sewing machine/needle and thread.
Step 1: Measure and cut what would be the back of the case. Make sure to cut room for flaps for pockets.
Step 2: Cut 2 pieces the same size to fit your inner square.
Step 3: Iron all pieces.
Step 4: Iron back and front together using Interphase (or you can sew)
Step 5: Iron large flap, by folding over so you can begin to see the final result.
Step 6: Start sewing everything into place!
Step 7: Be proud of your work!