Classes
Basically, Class Types give your classes and workshops more clarification. To use high school as an example, you may create a Program called "Classes." But various Class Types of that Program may be, "Algebra," "Biology," "Social Studios," and etc…. Class Types don't affect the behavior of your site as much as Programs do, but they help people find the services that they want on your Classes and Workshops Screens. For every Class Type you add, people can use the drop down boxes in the upper right corner to search for all classes or events (workshops) within that Class Type. This isn't where you type the actual name of the class. You do that later on the Class/Event Description Screen.
Events (Workshops)
Let's use the high school example to explain Class Types' relationship with workshops. If a high school created a workshop Program called "Camps," then Class Types for the Program might be, "Band Camp," "Cheerleading Camp," and "Senior Retreat." There isn't much different between the way classes and events are setup by this point. This isn't where you type the actual name of the event (workshop.) You do that later on the Class/Event Description Screen.
Resources (equipment rentals, room rentals, etc…)
The system treats resources a lot like it treats classes. If you rent and/or schedule your resources, they will eventually appear on the Resources Schedule Screen. Even if you don't schedule resources, you just rent them, then you still need to give each resource a Class Type. This helps give the resource another layer of classification. It also helps get the resource on the Resources Schedule screen.