Select Event-to-script Connection to display Event-to-script connection - Settings so that you can create an event-to-script connection.

An event-to-script connection displays in the Composition Editor as a single-headed arrow pointing toward the edge of the free-form surface.

A script connection is a connection between a part represented visually within the Composition Editor and code available to the composite part you are working on. Script connections provide a way to implement functions that are not provided by any of the parts of the application, but belong to the application as a whole.