iPhone or iPad
Direction to sync the school calendar to your iPhone or iPad:
Open "Settings"
Select "Calendar" (Before IOS 11)
Select "Mail" and "Accounts" (After IOS 11) 
Select "Add Account"
Select "Other" 
Select "Add Subscribed Calendar"
Copy and Paste the link: 
https://calendar.google.com/calendar/ical/rummelraiders.com_t2qojol7959koiqns0l3tepc70%40group.calendar.google.com/public/basic.ics
Select "Next"
Select "Save"

IMPORTANT NOTE:
DO NOT JUST CLICK THE LINK included above.  If you do that, it will only add the events currently on the calendar one time and not update your phone as events are added or edited.  You want to SUBSCRIBE to this calendar using the above steps so that you will get all of the updates. 

If you get an error message, make sure that you have copied the entire calendar address. It should end with ".ics".  If you do not have the entire address, you will get an error message. 
Android Directions
Submitted from a parent who shared directions about syncing an Android device:

From the google play store, install "iCal import/export".  (Note:The free version should be suficient, but these instructions are based on the professional version.)
 
Open the App and choose "IMPORT".

The next screen that displays shows the Import Source".  Select "Web" instead of "Internal/External memory".

If "http://" is displayed press it and select "https://".
 
Enter (or copy and paste) the following URL: calendar.google.com/calendar/ical/rummelraiders.com_t2qojol7959koiqns0l3tepc70%40group.calendar.google.com/public/basic.ics
 
Click the red arrow "->".
 
The calendar will import. 

The app will ask you for the tag to use to differentiate SCS events from other calendars on your device. Use "SCS". 

The events are now synced.