If you need to add a mailbox within Outlook the following steps should enable you to do this.
Adding a Mailbox
1. Within Outlook go to “File”
2. Then select “Account Settings”
3. Within the Account Settings window that pops-up you need to double click on your email address that is located in the “email” tab.
4. This will bring up a new window called “change account” and you will need to select the “more settings…” box in the bottom right hand corner.
5. This will now bring up another new window called “Microsoft Exchange” and you need to select the “advanced” tab along the top.
6. You will now need to select the “Add…” option and type the name of the mailbox you wish to add in to the “Add mailbox” pop-up window that appears.
7. Click “Apply” and then “Ok”.
8. You can now close the previous pop-up windows that appeared earlier and the new mailbox will be added to your outlook beneath your personal email mailbox.