How Much Do
I Really NEED to Know?
Like Scotty is saying, only YOU can answer that. The rest are suggestions on how that might be answered.
It really depends on your goals. Some are more musically inclined when they start, some are not.
When I started, I was musically inclined. I didn't know that at the time, but that's the way it worked out. When I started, I was 12 (man, I thought I'd been playing a long time until I ran into Kirk!) and I taught myself. I decided that my goals (are you kidding? I didn't have all my goals figured out, but they eventually went that way) were to be able to play chords and sing in front of people.
So that's what I set out to do. And I began playing in public three weeks after I picked up a guitar. Did I sound great? Are you kidding??? The point is that I had a broad goal and went for it.
What are the minimum things to know??? Chords and rhythm, if you ask me. Hey, the whole world of guitar is wrapped up in learning to play chords and learning to play rhythm. All the rest is a break down of the chords into their musical components from there? Why not concentrate on the larger picture right off the bat???
I learned very minimal theory and concentrated on chords, chord formations,
CAGED and how to play different strumming patterns. I didn't play anything resembling single notes for the first five years of playing. I was too busy playing rhythm and singing.
But that's just me. The thing is though, this works. The guitar is logically and mechanically layed out. Conquer the mechanics so you can spend more brain power on theory later on down the road. It IS a journey, and you're not going to arrive in one year or ten of playing.
Learn how to sing. Either to yourself or out loud, but this will help make you a musician and pique your interest for learning more about theory. Plus it's a huge benefit for training your ear and learning how to transfer what you hear to your hands.
Just make a goal for what the journey might be about for this year.
Have fun with it,
Steve