pages _wordpress_core

“hello everybody

I would like to create my theme in wordpress2.3 hosted by free.fr http://olivierbaudrydesign.free.fr i create my folder and inside i have 10 .css and i create file like index.php; biography.php ; thanks.php I used one or two css by file php, i create a menu like this :

in index.php you can see : <?php include $menu.”menu.php”;
?>

and menu.php is like this

<?php
$menuindex = <<<MENUINDEX
<ul id=”menu_oupocreanum”>

• <span class=”off”>home</span>
• <span class=”off”>biography</span>
• <span class=”off”>randomizer</span>
• <span class=”off”>workingprogress</span>
• <span class=”off”>play</span>
• <span class=”off”>videos</span>
• <span class=”off”>pictures</span>
• <span class=”off”>sounds</span>
• <span class=”off”>exhibition</span>
• <span class=”off”>software</span>
• <span class=”off”>abstracts</span>
• <span class=”off”>diagrams</span>
• <span class=”off”>machines</span>
• <span class=”off”>artists</span>
• <span class=”off”>bibliography</span>
• <span class=”off”>webography</span>
• <span class=”off”>discography</span>
• <span class=”off”>citations</span>
• <span class=”off”>lexique</span>
• <span class=”off”>forum</span>
• <span class=”off”>upload</span>
• <span class=”off”>thanks</span>
• <span class=”off”>links</span>

MENUINDEX;
$lines = split(“\n”, $menuindex);
foreach ($lines as $line) {
$current = false;
preg_match(‘/href=”([^”]+)”/’, $line, $url);
if (substr($_SERVER[“REQUEST_URI”], 0, 5) == substr($url[1], 0, 5)) {
$line = str_replace(‘<a h’, ‘<a id=”current” h’, $line);
}
echo $line.”\n”;
}
?>

but i think it’s possible to indicate at the wordpress’s core where are my pages index.php to thanks.php but where ?
is here a file in a folder when i can to do it?

thanks for every one who help me , i’m beginner , just understand html and css but php is an interest but want to learn it whith wordpress.”