If you use a Google account (e.g. gmail) and want to subscribe to this calendar with that account, make sure you’re logged into your Google account in this browser and click on the “+ Google Calendar” icon in the bottom right of the calendar.
If you have another calendar app or service, copy the link below and paste it where you are asked to in the app.
https://www.google.com/calendar/ical/hmug6hu9ks662bqdr3av28np10%40group.calendar.google.com/public/basic.ics
https://www.google.com/calendar/feeds/hmug6hu9ks662bqdr3av28np10%40group.calendar.google.com/public/basic