Durk,
Create a new directory under c:\wamp\www something like this
c:\wamp\www\testing
create a file called index.php in that new directory
Here is a simple example
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>My First Site</title>
</head>
<body>
<div style="background-color:red;color:white">
<?php
echo 'HELLO WORLD';
?>
</div>
</body>
</html>
If you now go to localhost again you should see a reference to your new folder (testing) under the "Your Projects" section of the wamp localhost page. Clikc it and it should go to your new site.
You can also get to it using [
localhost] and this way you wont need to go via the wamp homepage.