What must be clicked after choosing to create a new diagram?

After selecting to create a new diagram, the next step is to click on "Room." This is essential because it allows you to specify the type of space you are working with, which is crucial for accurate event setup. Choosing a room is a foundational step; it sets the parameters for the event layout, including dimensions, seating arrangements, and other important elements that will define the overall design of the event.

Selecting a room also enables you to incorporate specific features associated with that space, like fixed installations (e.g., podiums, screens), and provides a base upon which to build the rest of the diagram. This step is critical for ensuring that the event's requirements reflect the actual capabilities and limitations of the chosen venue.

The other options represent stages or settings that might be relevant to the overall process of developing an event diagram, but they do not serve as the immediate next step after creating a new diagram. Selecting a room is the first necessary action to begin the visual planning and layout of the event space.