There are lots of complicated answers here. All you need is to be able to build scales and chords using the circle of 5ths. Just learn how to write out the note

There are lots of complicated answers here. All you need is to be able to build scales and chords using the circle of 5ths. Just learn how to write out the notes for a scale like E major. Then learn how to write out the notes for all of the chords in that key. If you do this and learn how to build scales and chords everything will start to make sense. I have a music degree. This is the key. This page is a good start. https://www.tempomusicards.com/lessons/chord-formulas-and-the-major-scale/ https://www.tempomusicards.com/lessons/chord-formulas-and-th... I would also add that to really use theory you have to know the notes on your instrument. You can know them as audible intervals, letters and written musical notes. Tab is worthless. I learned to read music for school and it transformed my knowledge of the instrument.