In Office 365, each room and resource has its own separate calendar/mailbox associated with it. If you open a room calendar in Outlook, by default you will only see the availability information for all rooms. In order for you to see all details of the room bookings, you must have full admin access to that room. Only local room administrators are permitted to have full access to a particular room calendar.
If you want to manage room bookings calendar on behalf of your department, please submit a Service Request to the I.T. Services Desk. Once full access to the particular room was granted to you by the Office 365 administrator, that room will automatically appear under the "My Calendars" section in Outlook:
If you want to view the schedule for a particular room without seeing all details or being able to edit existing bookings, you can add the respective room's calendar to Outlook's Calendar section by following steps in this KB article: How to access and view a room schedule and bookings in Outlook 2013? Any calendars added this way will appear the "Rooms" section in Outllok.