Go back to the fundamentals first. https://www.musictheory.net/lessons https://www.musictheory.net/lessons Learn this by heart then learn it again! Best lesson

Go back to the fundamentals first. https://www.musictheory.net/lessons https://www.musictheory.net/lessons Learn this by heart then learn it again! Best lessons ever for Music Notation and Music Theory 101. Just keep in mind this is for the "western common-practice period", not some kind of intrinsic property of music. Then watch a lot of Adam Neely, learn on https://www.justinguitar.com/ https://www.justinguitar.com/ if you play guitar, and just devote lots of hours to the many, many, many free resources on the internet (which now you will be able to search for, since you will start to know the unknown unknowns). See you in a few years, the self-taught way is long but rewarding. Have fun! EDIT: Also, remember learning both horizontally (theory) and vertically (play the damn tunes!) It's easy to fall into the unidimensional growth trap.