Self-teaching since 2/3 years, with composition as main goal. First I spent some time identifying the main topics (music theory, counterpoint, form, orchestration, jazz, 20th century techniques, post-tonal theory, DAW, etc...) and finding appropriate books (r/musictheory and r/composer where great sources for that). Then, studying these books by taking notes and practicing (listening, composing, studying scores). These notes represent today ~20 PDFs and ~1300 pages.

Younger, I also studied piano and bit of music theory at school.

I must admit I spent more time studying theory rather than actually practicing. I'm currently working to revert that trend ^^