Good morning,
I want to add a layer selector to my map with openlayers. the selector logo appears correctly but nothing happens when I click on it. I’m looking but I can’t find it, thank you for your help, here is the code:

var map; // Declare the map variable globally to access it in other functions
var vectorSource;
var control;
var orthoLyr;
var planLyr;
var markers;

function initializeMap() {

    var osmLyr = new ol.layer.Tile({
    source: new ol.source.OSM()
});

    orthoLyr = new ol.layer.GeoportalWMTS({
        layer: "ORTHOIMAGERY.ORTHOPHOTOS",
                olParams: {
                    opacity: 0.7
                }
    });

    planLyr = new ol.layer.GeoportalWMTS({
        layer: "GEOGRAPHICALGRIDSYSTEMS.PLANIGNV2"
    });

    map = new ol.Map({
            target: 'map',
            //renderer: 'canvas',
            layers: [ planLyr, orthoLyr,osmLyr],
            view: new ol.View({
              //center: ol.proj.transform([ 2.35 , 48.85], 'EPSG:4326', 'EPSG:3857'),
              center: ol.proj.fromLonLat([2.2945, 48.8584]),
              zoom: 6
            })
          });


    vectorSource = new ol.source.Vector({format: new ol.format.WKT});

    markers = new ol.layer.Vector({
        source: vectorSource,
        style: new ol.style.Style({
            image: new ol.style.Icon({
                anchor: [0.5, 1],
                src: '#APP_FILES#marker3030.png'
            })
        })
    });


    map.addLayer(markers);

    control = new ol.control.LayerSwitcher();

    map.addControl(control);



   }



function styleFunction(feature) {
  return [
  new ol.style.Style({
    image: new ol.style.Icon({
            anchor: [0.5, 1],
            src: '#APP_FILES#marker3030.png'
        }),
    text: new ol.style.Text({
      font: '30px Calibri',
      text: feature.get('name'),
      placement: 'line',
      fill: new ol.style.Fill({
        color: '#000'
      }),
      stroke: new ol.style.Stroke({
        color: '#fff',
        width: 3
      })
    }),
  })
  ];
}

Gp.Services.getConfig({
    apiKey: "essentiels",
    onSuccess: initializeMap
});





var infoDiv = document.getElementById("info");
infoDiv.innerHTML = "<p> Extension OL version " + Gp.olExtVersion + " (" + Gp.olExtDate + ")</p>";

I want to be able to add the layer selector to modify the transparency, delete/display a layer….