Google Maps Marker Infobox

Hi,

I would like to have an Infobox appear one someone clicks on a marker on the Google Maps page.

Found this example code at Google for this type of behavior but I have no idea what file I have to modify

function initMap() {
  var uluru = {lat: -25.363, lng: 131.044};
  var map = new google.maps.Map(document.getElementById('map'), {
    zoom: 4,
    center: uluru
  });

  var contentString = '<div id="content">'+
      '<div id="siteNotice">'+
      '</div>'+
      '<h1 id="firstHeading" class="firstHeading">Uluru</h1>'+
      '<div id="bodyContent">'+
      '<b>Uluru</b>, also referred to as <b>Ayers Rock</b>, is a large ' +
      'sandstone rock formation in the southern part of the '+
      'Northern Territory,....

'+
      'Attribution: Uluru, <a href="https://en.wikipedia.org/w/index.php?title=Uluru&oldid=297882194">'+
      'https://en.wikipedia.org/w/index.php?title=Uluru</a> '+
      '(last visited June 22, 2009).

'+
      '</div>'+
      '</div>';

  var infowindow = new google.maps.InfoWindow({
    content: contentString
  });

  var marker = new google.maps.Marker({
    position: uluru,
    map: map,
    title: 'Uluru (Ayers Rock)'
  });
  marker.addListener('click', function() {
    infowindow.open(map, marker);
  });
}

also I found this example code opening and closing the infobox on a mouse over.

google.maps.event.addListener(CalMarker, 'mouseover', function() {
            //open the infowindow when it's not open yet
            if(contentStringCal!=infowindow.getContent())
            {
              infowindow.setContent(contentStringCal);
              infowindow.open(map,CalMarker);
            }
        });

        google.maps.event.addListener(CalMarker, 'click', function() {
            //when the infowindow is open, close it an clear the contents
            if(contentStringCal==infowindow.getContent())
            {
              infowindow.close(map,CalMarker);
              infowindow.setContent('');
            }
            //otherwise trigger mouseover to open the infowindow
            else
            {
              google.maps.event.trigger(CalMarker, 'mouseover');
            }
        });

        //clear the contents of the infwindow on closeclick
        google.maps.event.addListener(infowindow, 'closeclick', function() {
              infowindow.setContent('');
        });

I thank you once more for your great product and support. You are awesome!

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