Follow these steps to add one or more Public Folders to your Outlook account:
From the main Outlook window, select Tools, Public Folders.
Navigate to the folder, select the calendar you would like to add. Click on Subscribe. Continue subscribing to other calendars as needed and finally, close the window.
Outlook 2011 does not allow "side-by-side" viewing of muliple calendars. When you check more than one calendar, the appointments are combined into one calendar view. You will need to check and uncheck calendars as you view them.
NOTE: It is important that you select your calendar when finished. *Otherwise it would be easy to mistakenly add calendar appointments to the wrong calendar.