In the Filmstrip, click the slide for which you want to add a transition effect.
How to add slide transitions in Adobe Captivate
Transitions are special effects that appear when one slide changes to another. Transitions signal the end of one slide and the beginning of another.
In the General area of the Property Inspector, select one of the effects from the Transition list.
If you want to apply the transition to all slides, select multiple slides in the Filmstrip and specify the required transition effect.