Work&Operations
If it is free, book it now.
Check which rooms are free and what is already scheduled in one view, then set the date, time, room, topic, and meeting details.
The system checks for and blocks a clash at the moment of booking, so two teams never turn up at the same room at the same time.

Plans change, so bookings can be edited or cancelled — and the booking history is there to show how heavily each room is actually being used.