To specify the style sheet's location, set the href attribute to "style.css".

<html>
<head>
<style>
h1 {
color: red;
}

p {
color: blue;
}
</style>
</head>
<body>
  <h1>Water Puns</h1>
  <p>
Why are oceans so meticulous?<br>
They like to be pacific.
  </p>
</body>
</html>]]>

Make sure to pick href followed by = and finally "style.css".