In Protoplanet, a school is something that protos operate together to learn things in unique and interesting ways. Feel free to think about what a school could be, what it could be for, how long you might need it, when you might need it and why. It doesn't have to look like any other school you've every seen!
Different schools could look and operate totally differently from each other. A school can focus on just one aspect of things, or it can try to do a lot of things at once. You can even startup a school where protos work on designing other schools!
The important thing to realize is that you can design new schools. Design the different parts of the school, the ways things work. How do protos move around, in, and out of the school? What other schools can it be connected to so that everyone can do even more interesting and surprising things?