The ZIWO plugin is an Angular Web Component product. In order to integrate it into your environment you need to load the script and then you can use it.
<HTML>
<head>
...
<link rel="stylesheet" href="https://plugin.ziwo.io/ziwo.styles.css" media="print" onload="this.media='all'">
...
</head>
<body>
...
<ziwo-root></ziwo-root>
<script src="https://plugin.ziwo.io/ziwo.polyfills.js" type="module"></script>
<script src="https://plugin.ziwo.io/ziwo.plugin.js" type="module"></script>
...
</body>
</HTML>