Once you click on the link in “Slideshow: view” you are shown the first slide, and then you move backwards and forwards through the slides by doing either of the following:
- using the
<and>controls found at the bottom left of the slide - using your keyboard’s left and right arrows.
But you did get me to realise something: when you are first shown the first slide, if you want to use the arrow keys, you can’t do that without first clicking on the slide first. I guess that’s a SpeakerDeck feature.