When you’re creating or editing a slide presentation, you can add speaker notes to any slide by simply clicking and typing in the box situated below the slide:
Drag the horizontal bar above the speaker notes section up or down to allow suitable space for the notes. You can use the normal text formatting options from the toolbar to modify the information you enter.
To view the speakers notes while presenting your slides, click on the gear icon at the bottom of the screen and choose Open speaker notes:
Since the speaker notes will open in a new window, it’s best to use a two-monitor setup (e.g. your laptop and a projection screen) and move the notes to the screen only you can see, or else they will be visible to your audience.