<link href="https://assets.calendly.com/assets/external/widget.css" rel="stylesheet">
<script src="https://assets.calendly.com/assets/external/widget.js" type="text/javascript"></script>
<script type="text/javascript">
  window.onload = function() {
    Calendly.initPopupWidget({url: 'https://calendly.com/yourname/meeting'});
  }
</script>