You can add notes to any slide to help you present. You can refer to your presenter notes during your presentation if you’re showing your presentation while connected to an external display. In this case, you must set up the presenter display layout to show presenter notes.
Click View 
in the toolbar, then choose Show Presenter Notes.
Type notes in the white area below the slide.
To apply text formatting to the presenter notes, use the controls in the Format inspector.
To hide presenter notes, click View in the toolbar, then choose Hide Presenter Notes.
To view your presenter notes during a presentation, you must be showing your presentation on a connected display. The notes show only on your computer screen, so only the presenter can see them.
Click 
to enter presenter display mode, then click 
.
Select Presenter Notes.
Press the Right Arrow key or Space bar to advance through your presentation.