The UofC has a pretty good power skating course for adults. It's good for adults who can kind of skate (or at least go forwards).
They teach you skills like edge control, stopping on both sides, cross-over turns, skating backwards. You are allowed to bring sticks and gloves too which helps with balance.
I took it a few summers ago, so I'm not sure if they offer it during the winter months, but I am sure there are other venues that offer power skating courses.
The best way to learn is to take the lessons that you learn from the power skating course, and just hitting an outdoor rink and practice for a few hours a week before your next lesson.
https://www.ucalgary.ca/ActiveLiving...-Power-Skating