To add a school calendar to your Outlook for Mac app, follow the instructions below.  

1. From Outlook click Calendar

2. Click Open Shared Calendar, then type the name of the calendar you wish to open.  For example for JH Calendar you would type JH School, click Open

4.  First select Always use my response for this server and then click Allow

5. Shortly you should see the Calendar(s) depending on your access and permissions.  If you don't see the calendars contact the calendar administrator or IT for access.