Download the zip file from the site and upzip it. Make sure you have the below meta tag
<meta charset="utf-8">
Add javascript to the html header
<script src="path/to/myeventcalendar.js" type="text/javascript"></script>
Initialise a calendar
MyEventCalendar("#id to add calendar", {options})
Full Sample
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<script src="myeventcalendar.js"></script>
<script src="jquery-3.3.1.min.js"></script>
<title>My Event Calendar</title>
</head>
<body>
<div id="calendar"></div>
<script>
$(document).ready(function(){
MyEventCalendar("calendar",{theme:"santa", showAddEventButton:true, sources:["http://localhost:9000/events"], target:"http://localhost:9000/events", isAdmin:true});
})
</script>
</body>
</html>