Begin by using
embroidery software to print templates of your "DL" files, you will need
these to cut your patch fabric shapes. If you don't have embroidery
software, you can stitch the shapes out onto the fabric.
Here's more information on printing or stitching dielines.
You should end up with 3 fabric pieces -- a front, a back, and a
detail piece. Carefully cut the center holes out of each piece. It helps
to first mark an "X" in the center with a razor knife then use scissors
to cut the hole out.