
Kathryn S. answered 07/08/19
Musician and Former Music Major
The book you should probably start with is The Chord Wheel: The Ultimate Tool for All Musicians
by Jim Fleser. It's great for people like you who only know tabs and chord charts. My favorite thing about it is that it teaches you how chords relate to each other and form keys. This, in my opinion, is something few (untrained) musicians understand but all must know in order to compose effectively.