To add classes to a students schedule the first day of each scheduling term must be completely defined. For elementary schools only the first day needs to be defined. For a middle school the first day of each semester. Trimester intermediate schools need the first day of each trimester. High schools may need the first day of each quarter.
To setup the school calendar choose School and then Calendar Setup. The first day should be set according to the example below. Notice the Day, Schedule and Type must be set. See the ? (help button) at the top right of the PowerSchool page for more information.