If you want to add the Grace for Dover: Arise Calendar to your own Google Calendar or smartphone, follow these steps from Google:
Subscribe to calendars in Google Calendar
To add a calendar using its address, follow these steps:
1) Click the down-arrow next to Other calendars
2) Select Add by URL from the menu
3) Grace for Dover’s iCal address is: https://www.google.com/calendar/ical/ndsnj3dbkjmepqgeb2vg2qnsr8%40group.calendar.google.com/public/basic.ics
4) Enter the address in the field provided
5) Click the Add Calendar button. The calendar will appear in the Other Calendars section of the calendar list to the left.