A little bit of Easy 6502 [0] but mostly Richard Haskell's Apple II-6502 Assembly Language Tutor [1][2] along with Virtual][ [3] . Basically I'm trying to use assorted manuals I could find in my childhood home's basement, most of which seem to be out of print (although there are some books floating around on archive.org).

[0] https://skilldrick.github.io/easy6502/

[1] https://www.amazon.com/Apple-II-6502-assembly-language-tutor...

[2] https://archive.org/details/Apple_II_6502_Assembly_Language_...

[3] http://www.virtualii.com/