The following tutorial steps through the process of how to add a shared folder or mailbox to your account within the Outlook Web App. These steps are the same for individual mail folders (e.g. Final Project) as well as shared mailboxes (e.g. department accounts).
Shared folders must be manually added to your list of folders. Right-click the account you wish to add the folder to and then select Add shared folder...
In the Add shared folder window, search for the name or email address of the person sharing folders with you.
Select Add once you find their account.
The added folder or mailbox will appear on the left side of the window on the list of email folders. Select the folder to expand and display its contents.
If you need to remove a shared folder or mailbox from your account, right click on the folder's menu heading and select Remove shared folder.