This tutorial is geared towards people who have a basic to moderate working knowledge of sewing machines and would like to try some trickier feats. I would suggest looking at this tutorial for beginners. If you're really new at this, check out this tutorial on how to use a sewing machine.
Step 1: Gather your materials!
1 yard of fabric, I suggest something sturdy-ish like canvas or broadcloth. You may use 2 different fabrics as I did for the inside and out.
1 zipper, I chose a standard 6 inch zipper, you can you chose bigger or smaller, as long as it is not longer than half the circumference of your chosen circle template. (we'll calculate that later).
some thread, pick something that matches your fabric.
You need a sewing machine, all it needs to do is a straight stitch.
Bobbin loaded with thread
Pins (I'm a slacker, but you may find pins useful to keep your layers together.)