In your Outlook, go to the File Menu, click the Info Tab on the left, Account Settings drop down, and then Account Settings from the menu

When the  opens, click the Email Tab in the upper left, then click the New button

A startup wizard will open. Click 'Next'

Click 'Next'

Type in the shared mailbox in the Email Address field. Click 'Next'

It may take a few minutes to connect. 

You will be prompted to enter your username and password.  You will need to change the username from the shared email address to your Park ID number followed by "" (  Then enter your password in the password field, and click OK.

Once connected, you will click 'Finish' 

Finally, you will need to completely Exit Outlook and restart it

You may wish to add a signature for your Shared Mailbox that is different than your personal signature.  The link below will show you how:

How To Add A Signature To A Shared Mailbox In Outlook