PHP Help with organizing

[Sugartonic]

I have seen out of sites that use if statments to basically display their pages rather then numerous .html pages, and I know about where you get the whole index.php?area=pagename but how to you categorize them with the if statements. something like index.php?category=1&area=pagename.

For example

Code:

            <?php
if&#40;$_GET['area'&#93; == 'namehere'&#41; &#123;
?>

<?php
&#125;
?>

 my other question is do you actually when your making a link to it do you make it like..

Code:

<a href="index.php?area=pagename">Link</a>
or would you like do something like
<a href="area=pagename">Link</a>

I had someone explain this to me awhile back and I have been on php.net to look up how to categorize them but i cant find anything about them. I hope that my question is not confusing or anything, and thanks for any help that anyone can provide, or if you have a link to a place that can describe this, cause i most certainly can not find one out there.