Edit in JSFiddle

function go() {
    var photosLyr = new ol.layer.GeoportalWMTS({
        layer: "ORTHOIMAGERY.ORTHOPHOTOS"
    }) ;
    var roadsLyr = new ol.layer.Tile({
        source : new ol.source.GeoportalWMS({
            layer: "TN.RoadTransportNetwork"
        })
    }) ;
    var map = new ol.Map({
        target: 'map',
        layers: [
            photosLyr,
            roadsLyr
        ],
        view: new ol.View({
            center: [288074.8449901076, 6247982.515792289],
            zoom: 15
        })
    });    
                    
    var getFeatureInfo = new ol.control.GetFeatureInfo({
        layers : [
            {
                obj : roadsLyr,
                infoFormat : "text/html",
            },
            {
                obj : photosLyr,
                infoFormat : "text/html",
            },
        ],
        options : {
            auto : true,
            active: true,
            defaultInfoFormat: "text/html",
            defaultEvent: "singleclick",
            cursorStyle: "pointer",
        }
    });
    map.addControl(getFeatureInfo);  
    var layerSwitcher = new ol.control.LayerSwitcher({});
    map.addControl(layerSwitcher);
}

Gp.Services.getConfig({
    apiKey: "jhyvi0fgmnuxvfv0zjzorvdn",
    onSuccess: go
});

var infoDiv = document.getElementById("info");
infoDiv.innerHTML = "<p> Extension OL version " + Gp.olExtVersion + " (" + Gp.olExtDate + ")</p>";
<div id="map"></div>
<div id="info"></div>
#map {
    padding: 5px;
    width: 100%;
    height: 600px;
    box-shadow: 0 0 10px #999;
}

#info {
    padding: 5px;
    width: 100%;
    height: 20px;
    font-family: "monospace";
    font-size: 10px;
}