Attach interfacing to the wrong side of the garment over the pocket area.
Transfer the pocket markings to the right side of the garment and to the wrong side of the pocket jets. Draw in a box on the jet to make sewing parallel lines easier.
Place the jet on top of the garment with the right sides together, matching up the markings on the jet so that they sit directly over the markings on the garment pieces, and pin in place.
Sew along the long sides of the box on the pocket jet, making sure that both rows of stitching are parallel and the same length. This is very important for accurate jets!