Ok, I'll do my best. This is where my newbie side really shows up. Perhaps these are stupid questions, but for some reason it doesn't want to get through.

Keys - How do I use them with a song? As far as memorizing them goes, is there a convenient way about it? So many chords, how would the variations of a Dm chord work with a key, let alone every other chord?

Scales - How do they tie in with keys? How do I know what scales are in which keys? I don't even know all the notes on the neck of the guitar, is there any recommendations on how I can make that one come together?

Modes - Hell, I don't even know what a mode is.

Chords - There's, like 10's of thousands of them, if not more. Where do I start?

I feel kinda dumb for not knowing such questions, or at least having a rational grasp on them, and they seem even dumber to me having typed them out and seen just what it is that blows my mind, but I guess I'm not gonna learn if I don't ask anyone that already knows. I'll sacrifice a moment of ignorance for good skills. Recently (more so than before) I really wanted to learn to write songs as best as I could, and making things up constantly from scratch just isn't doing it. I'd appreciate any form of help. Thanks.