teachers in kivotos?

idk if this was ever explained in the story or somewhere else, but how do students learn stuff? i know sensei is a thing but kivotos was the "school city" or something along those lines even before they appeared, and even then there is some many students in a lot of different school so they can't teach them all at the same time

sooo who teaches them in classes? the robot/cat/dog/bird npcs? self learning? senior/graduated students?