The left and right arrow keys can be used to navigate through the slides. That might not be so easy if viewing on mobile! Update: Tapping/clicking the bottom right of the slide shows controls that allow navigation forward and backwards.
At the end of the presentation it mentions that it’s created using S5 https://meyerweb.com/eric/tools/s5/
Left and right arrow keys didn’t work for me (nor did up/down, or home/end, or scroll, or right click to go back, or clicking on the left hand of the screen to go back).
According to the S5 documentation, these should work https://meyerweb.com/eric/tools/s5/features.html#controlchart
There’s some more detail on these changes in this post: