Ditto! Using another solution that works well, can save you 100's of hours in your own time to get all the nuances just right!
You must validate that a room is not booked more than once. This can be by day and/or by hour and/or by minutes, even! So if someone requests, the "Green Room" on 01 Jan 2018 at 3:30 PM to 03 Jan 2018 at 12:00 PM, you must account for that room as "reserved" for all that time. The next user cannot ask for the same room on 02 Jan 2018 at 8:00 AM, as it is already booked.
You might research "FileMaker Schedule" in this forum and elsewhere for other suggestions.