Click on the photo in the center to start the slideshow.
You may not have any trouble, but depending on your internet connection speed, you may end up waiting a little bit for the video to "buffer" after you select it to play. Hopefully it works just fine!
There is music with the pictures, turn it up if you want :)
Or you can mute the music by clicking the little button in the lower right.
Pausing Slideshow: click play button, lower left. It will turn into pause/play.