Thanks to the efforts of @maximilian we now have a comprehensive Puppet configuration chapter as part of our overall guide to managing hosts: Managing Hosts
This is a huge improvement on what was available to the community to date.
A huge thank you to @maximilian
EDIT: Please note that doc PRs are always welcome! GitHub - theforeman/foreman-documentation: Documentation for the Foreman Project and its ecosystem - if you’d like to contribute docs and you need help, feel free to write to me!