How to edit map

You can use “showAsSelected” property of those countries:

https://docs.amcharts.com/3/javascriptmaps/MapArea#showAsSelected

I.e.:

var %CHART% = AmCharts.makeChart("%CHART%",{
  ...
  "dataProvider": {
    "map": "worldHigh",
    "areas": [
      {
        "id": "LT",
        "showAsSelected": true
      },
      {
        "id": "FR",
        "showAsSelected": true
      },
      {
        "id": "US",
        "showAsSelected": true
      }
    ]
  }
});

I hope that makes sense.