When you are on the main calendar page, click the link that says ‘Notifications/iCal Feeds’
In the window that appears, choose the calendars to which you want to subscribe, by highlighting them and clicking the > arrow to add them to the ‘selected’ box.
Select the email tab if you want to be notified by email or the iCalendar Feed tab to feed your selections into the calendar that you use. (ie. Outlook or Google)