How to sew Welt Pockets of a Hidden Button Bal Collar Coat

Main fabric : like a kind of Polyurethane (No information in detail) and it shrinks slightly after a certain period of time has passed after ironing. Lining of bodice : Sleek Lining of sleeve : Polyester Full lining. Hidden button placket. Bal collar. Raglan sleeves. Welt pockets. Inverted box pleat at the center back. Waist and sleeve belts. In this shooting, the feed dog of the sewing machine were not in good condition, and amount of stitches was increased. The white strip is just a “PP strap“ that is