I love it when I can answer an email to help someone move forward in their sewing. Pockets seem to be a problem for some and I know just where you are coming from as a beginner sewer. When I started sewing for the kids if any pattern showed a pocket I would either just leave it off or not buy the pattern. Yup, I was scared of those pesky things. Once I found out how easy they are to do pockets went on everything. Side pockets can see hard but they are not hard at all. Now, I will add an exception to that remark because if you happen to pick up McCall's pattern M4364. The way they show to put in side pockets will send your project to the not to be finished pile. I tried that pattern and the instructions are way off base. I have a feeling that who ever wrote those instructions have never put in side pockets.
First pick a good pattern, for me that is Kwik-Sew 2604 or any boys shorts pattern by Kwik-Sew. They show you how to put the pockets in while your project is flat and before you sew anything else.
As you can see this is a well used pattern. The shorts will be sewn using madras plaid.
You will want to use a fusible interfacing on one side of your pocket, pockets get lots of use keeping those frogs in so you want them to be strong. You will want to mark your sewing line on the pocket piece. Now pin the right side of the pocket to the right side of the shorts, stitch following the stitching lines marked. Clip seam allowance in the corners. Turn the pocket to the inside and press, top stitch 1/4'” from the edge.
Now, you will pin other pocket to the pocket on the front, right sides together, and matching notches and raw edges together. All this being done just on the front piece while your work is still flat.
That's it pretty easy, now just sew the back to the front on the seam line and you have side pocket to hold all those treasures little boys find.