There’s boards across school campus (one is found by the front gate, back gate, then one near the cafeteria) that have each class period/break listed with their times. You can as well ask any receptionist at the receptionist desk for a school schedule.
do note that there is not always classes every school day, it depends when the teachers/professors are able to host a class. They’ll make an announcement when a class is being hosted before that class period.