Yea, you have to admit that your jeans have holes. Done.
Step 2: Finding a donor
Usualy I sacrifice bottom pockets. Yes, it's cruel, but they are perfect size, color and i don't have to sew the edges.
So you need to carefully rip the seams. Don't damage jeans! Or you will have some more holes..
Step 3: Covering The Hole
Cover hole form outside, see if it fits. (actually you had to do it sooner- just don't wait till your holes are Pizza size and you'll be fine).
Choose how exactly you want the pocket to be sewn on. Attach it with pins.
Step 4: Sewing
Hopefully you know how to sew. Just choose the right color thread and a nice needle, or you can do it with seewing-machine (witch I don't have- I do all the sewing by hand.. Oh..).
Step 5: Be Proud
So you've done all steps. Congarts! Now be proud that you gave second life to your jeans. Put on your repaired jeans and have a PARTY!