Pull the pocket piece to the Wrong Side of the garment through the cut opening.
Arrange the pocket in place and flatten the opening by pressing.
The pocket has a 5mm welt on either side of the opening. Crear, fold the lower part of the pocket up 5mm then fold back on itself again as shown. This welt will reach midway to the centre line of the pocket. Pin in place.
Repeat for the upper welt.