Diablo 3 difficulty help -explain? ps3?

10/12/2013 13:30 love19801#1
Hey guys, I bought Diablo 3 last night.other than being good at actually playing it, in a total and admitted noob to Diablo. I'm a wizard, after paying almost every class to level 5 I went with him, probably witch doctor next.

My question is shot the difficulty of the game. First of all, I'm paying on normal, not hard.well I unlock anything by paying on normal?

When should I boost up the difficulty? HOW do I boost up the difficulty?

Also how does online work? I want to play with some random people! Thanks.