1. Open Outlook 2013 and click File 

  2. Click Info, then Account Settings, then Account Settings again.

  3. Highlight your current email account and click Change.

  4. The Server Settings box should appear, click More Settings.

  5. Click the Advanced tab, then click Add.

  6. Type in the name of the shared mailbox you want to add and click OK.  

  7. Confirm this is the correct mailbox by verifying the right name has appeared in the list, and then click OK to save your changes.

  8. Click Next to continue.

  9. Click Finish.

  10. Click Close.

  11. You should now be able to find your newly added mailbox over on the left-hand side of your Outlook screen, apart from your own.  You will need to click on the triangle to expand the folders.