This was always a favorite site of mine (it's in the first link)
http://www.exrx.net/
It will break down exercises and show the muscles groups - easy to "get" if you know what I mean.
It's always hard to start something especially when it's new and you don't want to make an a** of yourself. (I hate starting new things for that very reason even though I know logically that I'll love it once I "get it".
Old dog = hates new tricks
LOL!