The Navigation icons are all in the top left hand corner. Hover the mouse over an icon for information on its function.
If you find yourself a little lost the Home icon will take you back to the beginning.
One way to explore is to use the Name Index which lists everyone, grouped by surname. Clicking on a person's name will bring up a page with their details.
Similarly there is a Family Index.
Perhaps the easiest way to get started is with the Family Tree diagrams. The Tree icon will take you to them.