Learn how to annotate an animation.
In the storyboard timeline, move the playhead to the time to display the callout.
Click the Create Callout .
Click to place the annotation in the canvas or select model geometry to attach the annotation to a specific component.
In the Annotation dialog, enter the text for the callout.
Click OK.
Drag the callout along the timeline if necessary to set the time at which the callout becomes visible in the environment.