What is the first step to adding a new floorplan to an existing event?

The first step to adding a new floorplan to an existing event is to click on the diagram. This action allows you to access the visualization and management section of the event's setup, where you can begin to create or modify the floorplan.

By selecting the diagram, you're opening up the tools and options specifically designed for spatial arrangement. This is essential because a floorplan is a detailed layout, and you’ll need the diagram interface to accurately define the spaces, placements, and overall configuration you want for the event.

The other options, while related, do not directly lead to the necessary interface for creating a new floorplan. Clicking on the event generally opens the main event details but does not give you immediate access to the floorplan tools. Selecting 'new layout' or 'floorplan' would come after accessing the diagram, as these are actions you take once you're in the right section to start editing or creating the layout.