Questions about Wicca/Witchcraft? Please help, I'm a beginner!?

I am trying to do witchcraft, and some sites say you have to study almost everything wiccan before you can do spells, and some say you don't have too. Do you have to know everything before you start or just the basics? If so what are the basics? Also I beileve in god, but not any specific religion, so can I still do witchcraft without being wiccan? Please hlp me. All answers are appreciated. -Ashley