In 2016, YouTuber Julian Cianciolo explained the often confusing task of reading sheet music in a rather humorous way, offering simple explanations for the most complex concepts and noting specific exceptions to the rules.
The two main clefs, treble and bass, are connected by a middle note we call C. You’ll find that a lot of music stuff is based around C, except tuning; that’s based around A. Unless you play in a band and it’s based on the note right above A. That is, assuming you play an instrument that calls notes what they actually are.
Cianciolo goes into more detail about these confusing musical conundrums in “Things in Music That Are the Same but Aren’t”