The main thing you need is the managed locations addon - see
https://www.jevents.net/download-area/silver-downloads/462-managed-locations
Create your rooms as locations - if you have multiple rooms at a venue then each needs to be a 'location'
Make sure these are shared/common rooms so that your event creators can select the venue they want to use.
Also you will want to configure JEvents to block overlapping events on the event editing tab of the JEvents config
This will mean that you avoid double bookings
Does that do what you need?
If you'd rather have set time slots for the rooms then we'd need to configure things differently - if so, let me know and I can advise you on this alternative approach