1) Open index.php with notepad.

2) Edit the line xmlhttp.open
(Change the url http://www.example.com/ to your domain/webhosting.

3) Open page.php with notepad.

4) Edit the line echo
(Change the html code to your html code to display your ads on each redirection.

Note: Currently the page.php is showing a adult advertising.

5) Copy your modified version of index.html and page.php to your site.
6) Make a test to check if everthing is working properly.
7) That's all. Launch index.html and create your short bitly links.