By default the map shows all eDoB entries and AT Lines, uncheck the boxes on the right to filter what is displayed.
Hovering over a symbol on the map gives you a super brief summary of the entry. Clicking a symbol on the map will open a tab showing the eDoB information on the selected entry.
Hovering over an AT Line will give you a description of the AT Line.
Right Clicking (or long touch on mobile) on any other point on the map will show the coordinates of the point.