These steps can be used to setup an Outlook profile for Mail Merge, exporting from shared mailbox, etc.
Part 1a: Adding a New Mail Profile
In Outlook desktop app, go to the File menu
Click on Account Settings and select Change Profile
Click OK.
Open Outlook. You will be presented with this window:

Click the Options > > button and then click New…
Name the profile the same name as the shared mailbox and press OK

Enter the shared mailbox’s email address and click Connect

In the next window, enter your (@douglascollege) email address – not the shared mailbox’s address.

Enter your password and click Sign in
Wait for the account to be added.
Uncheck the “Set up Outlook Mobile on my phone, too” option, then click Done
Part 2: Using the New Mail Profile
Now when you open Outlook, you will be able to choose either the shared mailbox profile or your regular user profile (often named “Outlook”).
Choose the shared mailbox profile and click OK

Outlook will open and display the shared mailbox’s email.
Once Outlook has opened you can use the shared mailbox for Mail Merge, exporting, etc.
Part 3: Finishing Up
When you have finished your mail merge, close Outlook and open it again. You will be prompted to select a profile. Select Outlook and click OK. This will return you to your personal email inbox.

If you need to perform a mail merge again, you will have to close Outlook and open it again, then choose the shared mailbox profile before opening Microsoft Word. In any other case, use your regular user profile (often named “Outlook”) to use your email normally.
Or if you prefer, you can Delete the SharedMailbox program and set your default profile to your original mailbox.