Does anyone know what rules are involved in a homeowner's association?

Ultimately, it’s whatever’s in the contract. Some HA’s are far more strict than others. I imagine that the HA will be happy to tell you what the CC&R’s are—most are quite pleased when folks WANT to follow the rules.

They can vary widely. They often cover things like trees and property condition. You will need to get a copy from the specific Homeowner’s Association.

they can range from what color you are allowed to paint your house, to how many cars you are allowed. They can be persnickety shits.

You have to go to your docs. Each community may be different.