The way I did this with a stats book was:

  1. Ten pages a day
  2. Do all the exercises, and redo all the ones you get wrong.
  3. Add anki cards for all the key terms, ideas, formulas, etc. The best textbooks include a summary the end of every chapter that you can double check your notes / anki against. Prefer cloze markup to question / answer cards -- more cards per "fact" but longer retention.
  4. Double check your cards against a source like Wikipedia for completeness / accuracy, since sometimes there's an author bias to content with.

This takes about an hour a day for #1 and #2, and an hour a week for #3/4 plus a few minutes a day extra in the Anki review queue. For this book, you're looking at about 2 months start to finish.