Instructions for the Timeline are located below it. If you have a slow connection, you may need to hit refresh to get the script to load properly.
Putting your mouse on the left or right of the slide shows what the next slide is. Clicking there moves to the next slide.
The navigation on the bottom of the timeline can be scrolled by placing your mouse on it, and dragging it in the direction you want the timeline to move. The magnifying buttons allow you to spread the dates out, or bring them closer together.