An interactive floor plan is only useful to a ticket buyer if they can see which seats are available, and which are not.
That is what the concept of an event is for. In seats.io speak, an event is a single instance of a concert, show or sports match. An event is used to keep track of which seat is booked or free; this allows you to re-use the same floor plan for multiple events, without having to go over the design process again.
You can create an event for a floor plan in 2 ways: either through the seats.io web application, or using the create event API endpoint.