Slide Presentations: The slides in the presentations emulate PowerPoint. Some are timed to advance on their own, others need your mouse click or use of the navigation bar at the bottom left.
Navigation: Your browser shows a "TAB" above to indicate you are in the site. As you enter a presentation, it opens in a new tab, so there will be multiple tabs shown. There is a small "x" on each tab - clicking closes that tab.
You move about in each presentation with a click of the mouse or the scroll wheel. [Or it may be timed]
The ESC [escape key] closes any presentation.