Product review (5 stars): Instructions
I bought a new disposal, but the tube that came with it was too short to reach the drain pipe, so this looked like the perfect solution.  I had a hard time figuring out how to install this thing, but I got it eventually.  I thought I'd search around and see if there were instructions online or if anyone else had problems.  Looks like I wasn't the only one, and I couldn't find instructions, so here is how I'm pretty sure it's supposed to work:

1. Pop metal flange over disposal end of tube.
2. Insert white flange into disposal end of tube, with cylindrical part extending into tube.  This is difficult, I had to squeeze it down into the tube and then pull it back up to get the flange to seat in the lip.  I was sure the tube was going to stretch or break, but it didn't.
3. Install rubber gasket onto disposal end of tube, flat side out.  There's a groove in the gasket that fits over the lip (which is now reinforced by the white flange).

It seats very securely to the disposal, and the bendy-straw-like bellows allows it to easily install to the drain pipe.