For All of Your Teams
Tap Schedule.
At the top right corner, tap the Subscribe to Calendar icon.
Select the calendar and click OK.
Follow the onscreen prompts to finish subscribing to the calendar.
For an Individual Team
Tap Teams.
Select the "Team" you wish to manage.
Tap Schedule.
At the top right corner, tap the Subscribe to Calendar icon.
Select the calendar and click OK.
Follow the onscreen prompts to finish subscribing to the calendar.