Q: reformat from lion to snow leaopard

Hi

I have realised that installing Lion was a big mistake.

There are so many things that I did on Leopard that Lion won't do. eg I run two screens can's play a movie while working on the other screen. Yes I have taken off mirror display. When I put it on full screen won't work.

I want to ge back to snow leopard. I have the install disks. I also have Lion downloaded via App store.

What are the steps?