i'd say watch some tutorials online............deffinintaly learn a back-handspring first.....btw y do you need to learn one?
unnecessary!
First off, try that shit on a trampoline first, if you break your neck, no more fs, which means america will crumble without you

Second off, at your first attempt, try it on an ELEVATED surface, scarier, but gives you more time to make the rotations
The greatest tip is remember to jump straight up, not backwards, you'll fuck yourself up doing that