When you create a calendar event, it will automatically schedule alerts to go out 1 day and 1 hour before the event. You can delete alerts in the schedule in Schoop Alerts. A scheduled alert can be found in the "show scheduled alerts" tab.
If you want to create quick, scheduled reminders for repeating events, do this in Schoop Alerts by creating a new alert, and setting the schedule options. You can then delete individual days from the schedule so that they don't get set when the school is shut, or an event is not occurring.
To find the scheduled alerts, they will be in the alerts tab. Then go to the tab, "show scheduled alerts". You can click on the schedule and delete.