The slide transition is the amount of time allocated for each slide to be reviewed by the audience. When showing a presentation you can set the transitions of slides, therefore not having to manually click your mouse during the presentation.

To set slide transitions, click the Slide Show menu and click Slide Transitions.

 

 

You will then see the Slide Transition pane on the right. You can use this pane to modify the type, speed, sound, time, and action for the transition between each slide.