It came upon me to re-read the emacs tutorial. Last time I read it was probably about 17 years ago. Things might have changed since then.
I picked up two things:
C-/ is undo and is equivalent to
C-h c gives you brief help on a keyboard shortcut. I was using
C-h k but that opens a new window which can be annoying sometimes.
C-h t takes you to the tutorial.