If you already know you have access for the mailbox, setup for the account follow below description.
- in the top Menu click Outlook and Preferences.
- Below the box: People I am delegate for:
- Click on +
- Write in the name on the mailbox.
- Mark the name and click ok.
- Close down any Settings window you have open.
- The mailbox appears in left window of your screen. Click on the ARROW to open it up. After a few minutes it will have synchronised.