I actually don't know what you'd search on those sites - I just know my recommendations list seems to cycle through a mostly endless series of music theory vide

I actually don't know what you'd search on those sites - I just know my recommendations list seems to cycle through a mostly endless series of music theory videos. But yes, searching for "music theory" and things like the circle of fifths, intervals, modes, scales, pitch, standard notation, and keys would likely turn up useful results. Mostly they'll assume you have an instrument (usually a piano) handy.