Here is what your html page should look like:
This is my heading
...and this is my sub-heading
Here is the sentence you typed!
Here is what your notepad should look like:
<html>
<head>
<title>My Page</title>
</head>
<body>
<H1>This is my heading</H1>
<H2>...and this is my sub-heading</H2>
Here is the sentence you typed!