Install
This is the repository archive. It installs, but the folder name will carry the branch suffix and updates will not flow.
Install straight from GitHub with WP-CLI:
wp plugin install https://github.com/nsukonny/pmpro-chapters/archive/refs/heads/master.zipUpdates itself. It ships its own updater, so new versions appear under Dashboard → Updates.
Add-on for WordPress plugin "Paid Memberships Pro". Make new post type 'Chapters' and link users by chapter with filter in users list.