Adding an Additional Mailbox in Outlook
Adding an Additional Mailbox on Windows:
To add another mailbox in outlook first head to this location 'File>Info>Account Settings'
In Account Settings, select your current Mailbox and click Change and on the next screen select More Settings
Select the Advanced tab and click 'Add', type in the name of the mailbox and click 'Ok'
Once finished click 'Apply' and your mailbox will appear at the bottom left of the page.
Adding an Additional Mailbox on Mac:
To add another mailbox in outlook first head to this location 'Outlook>Preferences>Accounts'
Click the Plus Symbol at the bottom left of the window and type in the email address of the account followed by the password (if applicable).
Click 'Done' and the mailbox should be on the left hand side of the page along with your email account.