This post is a sequel to http://www.roaringraw.com/creativity/crafts/sewing-shorts-pattern-making/
Step 1) Make sure the pairing pattern pieces fit together. Start with front pocket. It has 3 pieces as shown below: Front pocket piece, two attachments.
Use the reference unripped part of the old shorts to understand how they go together. Place the pattern pieces to see if they fit. If not make adjustments.
In my case one of the attachments pieces was not aligning properly because it was a tiny bit short and a wee out of shape. So I taped a piece of paper to make it longer and cut the needed shape.
The end result: