HELPPP!!!!! (super urgent plz read)

Hi! I'm glad I got your attention! I do have to say tho, I'm new to this website and I'd like some information on how to toggle it and change it to my liking! (Just basic stuff like how to change the background,,, adding background music,,, etc. :-P) Would be much appreciated, hell, if I get even one message it would blow my mind, that's it tho!!! THANX FOR READING!