Step One -- Login to your google account on your browser.
https://accounts.google.com

Setp Two -- Find the Team Calendar you want to add or use the full Athletlic calendar that shows all calendars.

https://www.fvhsboosterclub.com/Athletic-Calendar

or example

Just the football calendar -- https://www.fvhsboosterclub.com/FB-Calendar

Step Three -- Click the Add Button down at the bottom of calendar.

Step Four -- Next click add Button to add the calendar.

Step Five - Verify Calendars were added to your calendar.  You should now see both your personal and team calendars.