Use this link to look up the iCal address of the calendar you would like to add. LSSU Google Calendar iCal addresses
Step 1: Log in to your Office 365 account. Step 2: Click on the Calendar App icon.

Step 3: Click on ‘Add calendar’ in the top menu.

Step 4: Click on ‘From Internet’

Step 5: In the window that opens, paste the iCal address for the calendar you want to add in the ‘Link to Calendar’ field and then add a calendar name of your choosing.

Step 6: Click Save.

Step 7: Your calendar will now appear in the lower left column under ‘Other Calendars’.