I’m not OP, but I really should find a, ‘musical theory for guitar for absolute beginners’, because that’s not simple enough. Every so often, I look at a couple Youtube videos, see explanations like that, and I crawl back in my burrow for six more weeks of not learning musical theory.
I learned some basic music theory, but on the piano first. Key of C, where you’re using the white keys, made complete sense to my mathematical mind. I mean, the scale is just “the white keys”. Then, C-E-G makes the basic (or “root” or “one”) chord. And look, it’s laid out basically every other white key. Learn the other chords in C, then try other keys by moving that template up or down the keyboard.
After I learned it on the piano, it made more sense on the guitar, where the scale and chords are… well, messier. So I’m at the point where you are, trying to move from chords to lead guitar riffs. But without that underlying music theory I’d give up, because I wouldn’t know WHY I was doing it.
Rick Beato has some wonderful videos on YouTube. His “why this song is great” series gets into theory sometimes, and once you progress to modes, he da man.