Subscribe to calendar

From your calendar.google.com using a web browser, locate other calendars and click the + and Subscribe to calendar and type the name of the person or calendar you wish to view.

You may run across a calendar that does not show up when you search for it. This is the case if the calendar is not the users primary calendar. Primary calendars are visible within the organization as they're tied to email addresses directly, but not for secondary calendars (these require the full Calendar ID if the email invitation was missed or wasn't sent to a new group member).

From email invitation 

Emails are automatically sent from Google when you or a group you belong to are added in the section where a calendar can be shared with specific people.

Click the "Add Calendar" link from that email. Sending you to a special URL that includes the calendar ID.

Here are some examples

https://www.google.com/calendar/render?cid=BCA-Email-Address@bethel.edu

https://www.google.com/calendar/render?cid=bethel.edu_secondary_calendar_id@group.calendar.google.com

From Calendar ID

Following the information above to subscribe to calendar, enter the calendar ID in the search

Another option is to put the calendar ID at the end of this URL, put it in your web browser and go!

https://www.google.com/calendar/render?cid=