Do a google search on 'how to sew rip stop nylon'. There are lots of links that come up. Someone may be able to help on this board, but working with quilting fabric is much different than with this specialized material.
For instance, the suggestions on heavy thread and felled seams are great to make a sturdy construction, but I think you need to coat or otherwise treat the seams so you can inflate your creation. Sewing the rip stop puts a buncha little holes in the fabric. Don't think the air will stay in!