ok, I don't know much about all the theory stuff, in fact, I'm not even sure what a key is. but I do know I want to stay in one, currently the chords I'm using are: Am, Em, Dm, and possibly B major, not necessarily in that order, but how do I know what key I am in, or what other chords/notes I can use while remaining in the same key? I was kinda also wondering how to find chords that can match a mood, for example, an Am to me is kinda a sad sounding chord, depending on what other chords you use around it, but a G and D are pretty bright sounding chords, and I wouldn't want to use them in a sad song. maybe I'm just wierd.. but if you could answer one or both the questions, that would be helpful. thanks