Dave,
Just think of a cylinder with the lid on top, the drum on the bottom and the plastic in between.

It is basically a round lid from a 5gal drum at the top. The top of the plastic shower curtain hangs from the lid, held on with velcro.

The bottom of the shower curtain wraps around the bucket, also held on by velcro. You cut the curtain so you have just enough material to go around and have a 2or 3" overlap with a couple of velcro tabs to close it up after the film is hung. Use anything you want for a system to hang the film from.

If the place you hang it is fairly isolated without any foot traffic, you can skip the drum at the bottom and let the plastic just hang from the lid. I used the bucket because dust would get kicked up from people walking buy and the shower curtain material was not long enough to reach the floor when hanging from the ceiling.

You also don't need to have any vents, but it does speed up the process.

Hope this clears it up a little. If I can figure out how to use my Wife's new digital camera I will take a picture and then try to figure out how to post it.