This was helpful.
It would be even more helpful if this article could be updated:
https://generatepress.com/knowledgebase/install-activate-addons/
I was stuck at this part:
GP Premium
If you’re using GP Premium, you need to activate the add-ons you wish to use (to avoid loading unnecessary addons).
You can do this in “Appearance > GeneratePress”.
GeneratePress was missing from the Appearance menu because GP wasn’t installed as a theme. WP noobs like me need to be told that GP has to be installed as a theme. Thanks!