If you want to quickly add a booking into one or more than one tables in your Floorplan, you can drag your mouse around the Tables/Area (make sure to cover all tables entirely) which will produce a red box over the selected tables/area.
Once you have done that:
> Let go of the mouse
> The 'ADD BOOKING' tab will now appear to the Left-Hand Side
> Fill out the Booking Details> Click 'COMPLETE' at the bottom to finish placing the booking into the tables