Let's see. First, you will need a hole in the front because that's the pocket opening.
Usually, a pattern has you work the pocket linings first and set them aside. It sounds like you did this. However, I've always experienced pocket linings as the inside of the pocket. The pocket linings are the things you put in your bag. I don't think they're the outside of the pocket.
You're now going to work across the sweater up to the pocket, put the present stitches on a thread, and work the stitches from the pocket lining that you did earlier. The stitches that will now be on the thread are the top edge of the pocket. I'm sure at some point in the finishing process you'll put these back on a needle and finish the top edge of the pocket (and sew down the sides of the pocket lining to the inside of the sweater.)