1. Open up your Google Calendar
2. On the left-hand side of the calendar where it lists all of your calendars, go to "Other Calendars" and click the "+" to the right of it
3. From the options listed, select "From URL"
4. When prompted, copy and paste the following link on the page you are brought to and then click "Add Calendar":
https://calendar.google.com/calendar/u/0?cid=dGNuai5lZHVfNm9nOGoyZmxwbmM3NmZ1ZDA0cG1sZWNrMTBAZ3JvdXAuY2FsZW5kYXIuZ29vZ2xlLmNvbQ