To add a public folder calendar to Outlook, please use the following instructions. The screenshots in this article are using Outlook 2013. Your version may look slightly different.
1. Open the 'folder view'
Go to the Folders section of Outlook by clicking the ellipsis at the bottom of the window and choosing Folders.
2. Expand Public Folders
Click the triangle next to 'Public Folders - [Your Email Address]' on the left hand side of Outlook to expand the Public Folders list.
3. Expand All Public Folders
Click the triangle next to 'All Public Folders' to expand the list.
4. Add the calendar to Favourites
Locate the calendar you need access to in the list. Right-click the calendar and select 'Add to favourites...' This will now show under the Favourites folder.
5. Open Calendars view
Click on Calendar at the bottom of the Outlook window. The Public Folder calendar should now show under 'Other Calenders' on the left. Check the box next to it to view the calendar.