To manage your meeting room with Joan and Office 365 you will first need to create a Room resource in the Office 365 Admin center.
To create a Room resource in Office 365, log into "Office Portal" as an Admin user > Admin > Resources Rooms & equipment and click on Add.
To check your room resources in Office 365, log into "Admin" > “Admin centers” > "Exchange" at https://outlook.office365.com/ecp/.
Select "recipients" from the menu on the left. If the room you want to manage is not listed, add it to your resources by clicking "resources" > "New," and selecting "Room mailbox."
Enter the details of the room you want Joan to manage and click "Save."