How to open a shared calendar
Here are the steps to add a shared calendar to Outlook:
1. From your Calendar folder, go to the Home tab > Manage Calendars group, and click Add Calendar > Open From Address Book.
2. In the dialog window that opens, type the name of the calendar. In the displayed list find the calendar you wish to add, double click it, and click OK.
You should now see the calendar in the calendar list on the left of Outlook