The Index feature allows you to create an Index section in your book, that lists all students and staff in alphabetical order along with the page number(s) in which they appear. Names are automatically added to the index for Portraits. For Candids you will need to tag the photos (with the Face Matching feature or manually typing names) that you would like to appear in the index.
This article will take you through step-by-step on how to create your book's index pages.