We start with creating an HTML page for the app. There we define the meta tags, a script tag to load the SAPUI5 libraries, and a placeholder for the content of the app.
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta charset="utf-8">
<title>Hello World App</title>
<script src="http://<<server>>:<<port>>/resources/sap-ui-core.js"
id="sap-ui-bootstrap"
data-sap-ui-theme="sap_bluecrystal"
data-sap-ui-libs="sap.m">
</script>
</head>
<body class="sapUiBody" id="content">
</body>
</html>
Adapt the path where the resources are located (<>:<>) according to your installation. For OpenUI5 you can use src="https://openui5.hana.ondemand.com/resources/sap-ui-core.js". For accessing SAPUI5 on the SAP HANA Cloud Platform, for example, use src="https://sapui5.hana.ondemand.com/resources/sap-ui-core.js".