The maps will open in your current browser window. To return to this page ... use your "back arrow" at the upper left of the header at the top of the screen.
Click on a star at a map number to the right to bring up the full size map. Click on the map to zoom in or out.
Use the scroll bars on the map page to maneuver the map up & down or side to side.
The maps are LARGE (3-5MB) but the detail is excellent.
The colored areas are a "letter" group North to South from the DMZ area and down to below Quang Nai.
To download the large maps, right click on the opened map & "Save as" a file on your computer.