To gain access to a shared mailbox, you must first request access to it by filling out the request form which can be found here.
To add a shared mailbox into you Outlook client, please follow the steps below.
1. Select File > + Add Account;
2. Enter the email address of the mailbox in the 'E-mail Address' field (all other fields are not required);
3. Outlook will search for the mailbox
You will see a password box -please remove the email address from the text box; you need to enter:
Tick remember my credentials, then click OK, then OK again on the Add account box.
(See this guide if you require further assistance with the login box)
A summary screen will display when complete;
4. Outlook will then need to be re-started, click OK, then restart Outlook;
5. The mailbox will then show in the mailbox list on the left side.
Outlook online (webmail).
To access a shard mailbox via Outlook online (via Office 365), please follow this guide.