Looking for a plugin to add comments/study notes/observations to a score

Greetings,
I found one Plug in from a "deleted author" but it doesn't seem to work.
Any suggestions? Seems like I am missing something very obvious. My apologies. I would like to be able to write text as a study tool to scores as I progress in my studies.
How do other users add thoughts/comments/study notes to a score?

Any info will be greatly appreciated.
Thank you