I haven't knit many garments with pockets. (Some a pretty long time ago, well before the old blog.) Thinking that the last sweater I made with pockets was the Farmers Market Cardi, but that had a completely different way of making those pockets. There are the patch pockets, pockets with flaps, side-seam pockets, pouch pockets, cut-in pockets and inset pockets. (I may be missing a one or two.)
Inset pockets happen to be my favorite and the method of choice written in the pattern for my new project.
You make the lining before, then after you bind off the front piece, you pick up and knit across the lining stitches. Thus, creating a layer of pieces. Hence, your pocket!