I don't know what step it is, but you assemble the rectangle and the lining is larger than the front of the pocket. When you line up the raw edges the lining will roll to the front. Sew the side seams with right edges together and then turn. Leave the bottom open. To attach the rectangle to the front section you need to match the line they tell you to draw on the bag front with the raw bottom edge of the pocket. The pocket goes under the line, but up against it. So the pocket hangs down towards the bottom of the bag. You sew the seam and then fold it up against the front of the bag and then sew the finished edges down. I think that there is a tutorial with pictures that you can search for.