Copy this address:
https://calendar.google.com/calendar/ical/allenffacalendar%40gmail.com/public/basic.ics
On an iPhone:
Settings
Apps
Calendar
Calendar Accounts
Add Account
Other
Add Subscribed Calendar
Paste the .ics link.
Tap Next → Save.
On an Android Device:
Tap the FFA calendar link (.ics) provided by your teacher or copy the link.
Open Google Calendar on a computer or in a web browser if prompted.
Subscribe to the calendar:
If the link opens the calendar, click Add or Add to Google Calendar.
If you're asked to sign in, use the Google account you use on your phone.
Open the Google Calendar app on your Android phone.
Tap the ☰ Menu (three lines) in the upper-left corner.
Under your calendar list, make sure the Allen FFA calendar is checked so it appears on your phone.
If you don't see the calendar immediately, give it a few minutes to sync. You can also pull down on the calendar screen to refresh.