First mark the seam allowance included with the pocket pattern piece.
Without back stitching at the first and last of the stitch, sew a long stitch (3.5 or 4.0) at the outer edge of the curve 1/4inch or less from the sides. Leave long thread tails.
Place the template on the seam allowance markings that correspond to the correct curve on the template. Pull one of the long strings to gather the fabric up and over the template.
Secure the fabric with paperclips and use a little spray starch if starch is OK for your fabric. While holding the thread taut, press the curve with an iron. Let the template and attached fabric cool, then remove the template and press on the other side.
For the western pocket shape, skip the gathering stitch steps. Fold the seam allowance over the top of the template, secure with paperclips, press with a little starch (if appropriate for your fabric). When cooled, remove paperclips and template and press on the other side.
It makes an amazing pocket point!!