Garreg-Mach Monastery–which is home to the Officer’s Academy–serves as the hub area where you can teach during weekdays and partake in leisurely activities during weekends. In particular, you can freely explore the monastery when it’s the weekend.
Above is the map of the monastery that we’ve attempted to piece together. It seems there are at least 3 floors, with some sections being closed off at the start. The in-game map also allows you to skip travel to various landmarks and check the location of students.