When you are creating a class, you can schedule your class in advance. To do that, enable the “Scheduled” option, and then pick the date and time of your class.
After you clicked “Schedule”, you will find the class in the ‘Upcoming‘ category:
If you want to start your scheduled class, click on the “Start” button (make sure that your students are online before starting the class).
If you want to delete a class, click on the options button and then click “Delete“: