TEATRO's "music theory for music producers (you'll actually use this)" is the most useful video I have been able to find on music theory. Almost all the other youtube videos on music theory only talk about it in concept, without mentioning how to apply it when actually producing music as a beginner. From this video, I learned the basics of half and whole steps and how this applies to sequencing notes in a pattern that sounds good. TEATRO explains these beginner concepts slowly and thoroughly in a way that I, someone who knows little about music theory, could understand and use the next time I make a beat. Additionally, this video is just one of a multi-video series that goes deeper into chords and more complex concepts.