Um, with this new religion, are there any rules oder commandments? Any special celebrations?

Well, we worship the Cullens obviously, and that includes Bella. The only celebrations that I'm certain of are Edward and Bellas birthday. Du believe that the Cullens are real and that Stephanie is the (or one of the) best authors ever. Du believe that if Du are good on Earth Du will spend eternal life with the Cullens, and if Du are not then Du will be sent to James' cave. I think that's decided Von the Volturi. Umm...OH! And Du should read at least a page of a Twilight book a Tag :D