Very good points End User, I have to concede then that sessions would be better. Now that we have squashed my idea of the OP using cookies perhaps it would be a good idea to answer is original question as to how to use sessions.
Its something like this
<?php
session_start();
$_SESSION['My_Varable'] = "my_data";
echo $_SESSION['My_Varable'];
session_destroy();
?>
Basically you
1: Start the session
2. Assign valuables to the array, and assign values
3.Destroy the session when your done
Ill look around and see if I can find a tutorial for you.