Resources for Book Writing

I am the author of 10 non-fiction yoga books, so I know how to write from scratch.
This next project is a bit different.

I led a series of successful courses which produced more than 3000 pages of questions and answers.
Distilling that down into the Gems would be awesome.
Do you have suggestions or best practices for doing this?
Words of wisdom?
I am thinking of Brookes podcast book as inspiration.