Spinning classes are done in a fitness studio, with various light and music settings to create an energized atmosphere.
Instructors guide participants through workout phases. Warm-up, steady uptempo cadences, sprints, climbs, cool-downs, etc.
You control resistance on your bike to make the pedaling as easy or difficult as you choose. Constant adjustment is normal.
All you’ll need is workout clothes, a towel (to wipe your face) and a water bottle.
Spinning bikes have toe clips so you can wear tennis shoes. But many pedals also work with Shimano-style SPD cleats.
Here are a couple of interesting articles:
And as Karin mentioned it is a protected name.