You are basically sewing the hoop on like normal, just a different plane (veritically instead of horizontal). Everyone needs to cut a hole and loose tension. Push pins will give a lot of support. I would wrap it around the bottom. Melt the edges of the fabric after you cut it. Don't poke the needle strait through. Poke it through further up the fabric such that when it gets tight you pull the fabric tighter. To do this you will have a small bunch of fabric or else you will rip through the edges.
Hopefully that makes sense... Someone else feel free to re-word this better...
Scott