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You can follow the procedure from this link (https://calendar.teamup.com/kb/subscribe-to-teamup-icalendar-feeds/).
Basically, click the setting button on the right, choose Preferences then choose iCalendar Feeds.
In the next screen, copy the URL of the calendar you want to subscribe to. In your calendar application, add calendar Feed using this URL. For Google Calendar, you can find the instruction here. For the apple calendar, the instruction is here.