Step 1: Design and rough cut
after you design it give your pipe a rough cut around the general area you made with your maker. don't cut right on the line leave your self some room. It helps to leave it angler for when you cut it in half.
Step 2: Cut it in half
Once you have finished and sanded the insides smooth, dampen one side, spread wood glue, and clamp the pieces together for at least 12 hours depending on the glue. I believe the glue used sets in 3 hours and cures in 24. This is not a step you want to rush, for you will be putting a lot of stress on the wood when you round it. In the mean time you can work on the mouth piece.
(sorry no pictures, I forgot to snap them for this step. Look for an update soon:)