[sudo-discuss] Resources for music theory?

I'm specifically trying to get into orchestral composition. Currently I can read basic music notation and can play at least piano+guitar at a basic/intermediate level. I'd like to level up my theoretical understanding and at the same time get some experience composing. This looks ok, but a bit basic: https://www.coursera.org/course/musictheory Any recommendations for online resources / books / university lectures I can sneak into? -- marc/juul