Cut out your pattern
Stitch all around the edge leaving a gap so you can pull the fabric right side round.
I have left my gap on the right edge near the top. Once you have pulled the fabric around the right way place the other fabric back to back and stitch together making sure not to stitch past the clasp area!
Once the two pieces are together you can stitch in your clasp:
I used large pins to hold the fabric in place whilst I hand stitched around. And hopefully you will have something like this: