The Map.addMarker function creates a new marker at the position defined by latitude and longitude and adds the new marker to the Map object named map_name. Initially the marker will have the default red and black marker icon and no description.
You can customize the marker icon using the function Map.setMarkerText or Map.setMarkerImage. You can add a description of the marker using Map.setMarkerDescription. The description will appear in the marker list and in a popup when the user taps on the marker.