Yes you can use your exchange mail boxes. So you need the Room Manager for Exchange Version. All your exchange resources are maneged in Exchange Online.

The Outlook Add In (OAI) for Room Manager is an Office Add-In. Office Add In deployment is decribed here Deploy Office Add-in Microsoft Link

Office 365 Admin can share the office Add-in centrally in the Admin Center. End-user can add the Outlook Add-In from the Menu. Get Add-Ins.

The conference Room Display PowerApp runs only with the Room Manager Solution. So, in any case, you will need the solution to be deployed in your O365.

The Support and Maintenance contract is mandatory. It’s a recurrent fee, which is paid yearly. please check our Shop to find the details. There are 2 support packages available. All other licensing fees are one time.

Basic
Premium

You can connect from The Room Manager event calendar, where all your events are stored in the user’s Outlook calendar.

When the user opens Outlook they will see that the RM Calendar is under “other calendars”

Note: The events from the Room Manager Calendar are one way synchronized to the outlook calendar, which shows under other calendars. The room Manager calendar is the master. You can book an event from the Outlook calendar. You can only see the current events which are managed in RM Calendar

No. this is 2 different things.

with the connect to outlook, you connect the Room Manager calendar with your Outlook calendar (other calendars). A one-way synchronization happens. All your Room Manager events/Bookings are showing us a new calendar under your other calendars in outlook, The events are not added to the user’s personal outlook calendar. The Master is the Room Manager Calendar.

The Room Manager Outlook Add-In as an Office Add-In is installed on the users’ outlook. And made available for meeting requests, where the user can send a standard meeting request, meeting invite, invite the attendees and at the same time book a resource like rooms, spaces, catering, equipment, etc.