Pasha Agapov: yes, sorry, I didn’t find the videos until after I posted the question. And I spent awhile searching online to see if there was some standard I hadn’t known of, too. I really should have thought to look at developer’s website! The app is otherwise so straightforward to use, I hadn’t looked for tutorials. But I think an info button or a note in the settings would be a really helpful addition. Thank you for considering it.

J: Actually, there are also hints on the keyboard that give you the meaning of the symbols. But I guess you don't see them until you try editing a rhythm and look really close :)

Pasha Agapov: wow, the words aren’t there on mine!

J: True, it depends on the screen size too