Data Structures

Stuff like "staff" or "keyholder" or "public"

Things the person is considered allowed to do / teach

Stuff a person has learned which allows them to take advanced stuff or train an apparatus

Actual human beings

Where classes are defined, but not scheduled

Is there any reason private lessons shouldn't just be a type of class?

Where classes are scheduled

The types of classes there are (trampoline, intro, aerial, workshop)

Locations, equipment, etc

When people buy/use stuff