Here is an example of using the Combobox in a plain html page:
<html>
<head>
<link href="https://developer.temenos.com/uux/base.css" rel="stylesheet" />
<script src="https://developer.temenos.com/uux/unified-ux-web.min.js"></script>
</head>
<body>
<uwc-combobox id="combo" label="Select"></uwc-combobox>
<script>
const comboEl = document.getElementById("combo");
comboEl.options = ["Apple", "Artichoke", "Asparagus", "Banana", "Beets"];
</script>
</body>
</html>