You are going to sew inside the leg. Keep it right side out, seam down and put it behind the needle and carefully pull the leg under the pressed foot until you get to the end. The top of the leg will be crumpled behind the pressed foot. Just carefully sew along the seam line, and when you finish it will all be behind the pressed foot again. Hard to describe but not difficult to do. Many of old darlings learned to sew without a free arm. I never really got comfortable using it. I hope this made sense to you!