Create index.html with this structure:
<!DOCTYPE html>
<html>
<head>
<title>My First JS</title>
</head>
<body>
<h1>Hello</h1>
<script src="script.js"></script>
</body>
</html>
The <!DOCTYPE html> tells browsers to use modern standards. The script tag at the end loads your JavaScript after the page content exists. Save this template. You'll use it as a starting point for practice.