You can click on any of the markers to see more information about the position. You can use the buttons at the side to move between different markers, move the map, and zoom in or out. You can also drag the map by holding your left mouse button over the map and the moving your mouse.
NB: This map does not work with Internet Explorer. To see it properly you will need to use Firefox. I have tried to get it to work with Internet Explorer, but that browser gives strange errors. Life's too short...