Videos:
Heroku Platform Basics for Partners - https://www.youtube.com/watch?v=PDTsT0e3evQ
https://www.youtube.com/watch?v=AKbxVwzP11c
Trailhead Resources:
https://trailhead.salesforce.com/en/users/equek/trailmixes/heroku-for-partners-beginner
https://trailhead.salesforce.com/content/learn/trails/heroku_enterprise