How to link referral tails for free on the landing page (landing page)?

Question

Landing pages

I need to link referral tails for free.
I found instructions on the site http://referral-tails.rf/?p=47
But I don’t know where to insert this code, and the site owner takes a fee for linking referral tails - 1 thousand rubles. for 1 site.
Can someone help?
The code is attached:
How to attach a referral tail: php code to determine the so-called. referral tail. It's as simple as 1-2-3 and can be added to any site. (the code is attached below)
Then all that remains is the final variable (or its value, if 2 different scripts work) add the code of the script that sends the order to your mail in php.
Difficulties can arise only if you have a landing page purely in html, without php. In this case, I personally see a simple option right away. Rename index.html to index.php - the actual code can be added immediately, paste it into .
Code itself:
// define referer
$referer = $_SERVER['HTTP_REFERER'];
// look for addresses of search engines in the referer and assign
corresponding values ​​// to $search and $crawler variables
if (stristr($referer, 'yandex.ru')) { $search = 'text='; $crawler = 'Yandex'; }
if (stristr($referer, 'rambler.ru')) { $search = 'words='; $crawler = 'Rambler'; }
if (stristr($referer, 'google.com')) { $search = 'q='; $crawler = 'Google'; }
if (stristr($referer, 'google.com')) { $search = 'q='; $crawler = 'Google'; }
if (stristr($referer, 'mail.ru')) { $search = 'q='; $crawler = 'Mail.Ru'; }
if (stristr($referer, 'bing.com')) { $search = 'q='; $crawler = 'bing'; }
if (stristr($referer, 'qip.ru')) { $search = 'query='; $crawler = 'QIP'; }
// if the visitor came from a search engine, then execute the following code
if (isset($crawler))
{
// here we bring the referer into a human-readable form
$phrase = urldecode($referer);
// search for keyword in referer
eregi($search.'([^&]*)', $phrase.'&', $phrase2);
$phrase = $phrase2[1];
}