After working at Here School for some time, a teacher decides to quit working there and leaves to go work at another school.

This pilot episode of Baldi's Basics The Show is meant to show how Baldi got his teaching position at Here School, since after the other teacher left, Here School needed to hire a new teacher to teach math class, which (although not shown in the pilot episode) ultimately ended up being Baldi.—JohnsterSpaceProgram