1. Once you are looking at your inbox, look to the upper-right for a circular icon. This can contain your initials or your profile photo.
2. Once you’ve clicked it, click ‘Open another mailbox...’
3. In the pop-up that appears, begin typing the email of the Shared Mailbox until you see it in the list, then click it in the list.
4. This will open a new window with the Shared Mailbox email. You are now acting as the Shared Email.