You can add inbound iCalendar feeds to your Teamup calendar from other calendar services, such as Apple calendars. The first step is to get the iCalendar feed URL from the calendar you want to subscribe to. For Apple calendars, there are a few ways to get the iCal feed URL.
Option 1: Get the iCal feed URL from your Mac
Open the Apple Calendar app on your Mac.
Find the calendar you want in the calendar list on the left. Click the Calendar icon if the list is not visible.
Right-click on the needed calendar, then click Share Calendar from the pop-up menu:
Right-click on the needed calendar, then click Share Calendar from the pop-up menu:
Note: if you do not see an iCal feed URL in the pop-up information box (Step 4), you need to publish the calendar so that an iCal feed will be generated:
Check the box next to Public Calendar.
Click the Done button.
Then proceed from Step 3: right-click, select Share Calendar. The iCal feed URL should be shown now.