The JH Enterprise has provided instructions for this that include screen captures here https://johnshopkins.service-now.com/kb_view.do?sysparm_article=KB0012272
Adding via OWA(Web Version) on a Windows Device
This will allow a user to add the shared mailbox as a quick access point versus opening in a separate tab
Navigate to the Web Version of Outlook, either through http://Outlook.com or via the my.jh.edu portal
Once signed into Outlook, on the left hand panel you will see a drop down button that says "Folders"
Right click "Folders" and click add shared folder or mailbox
Type in the email X@JH/JHU.EDU
This will add the mailbox to the Web version of Outlook
Adding via OWA(Web Version) on MacOS
This will allow a user to add the shared mailbox as a quick access point versus opening in a separate tab
Navigate to the Web Version of Outlook, either through http://Outlook.com or via the my.jh.edu portal
Once signed into Outlook, on the left hand panel you will see a drop down button that says "Folders"
Hold down the CONTROL button at the bottom left of your keyboard and click "Folders"
Click “Add shared folder or mailbox”
Type in the email X@JH/JHU.EDU
This will add the mailbox to the Web version of Outlook