They usually go in a separate file.. Depending on the how it's being used in Zen Cart they could be in a language folder, a class folder, a functions folder, an extra datafiles folder or even an extra configures folder in Zen Cart.
Do a search through your store using the developers toolkit (search for "define(") to look for existing examples to see how you would construct one.
For Edit Orders there is one similar to what you are trying to do. From line 21 of admin/includes/extra_configures/edit_orders.php
Code:
define('FILENAME_ORDER_EDIT', 'edit_orders.php');
Super Orders also uses a similar file to point links to the orders.php file

Originally Posted by
ScriptJunkie
Ok, I found a tutorial at w3schools.com on how to write a PHP define.
The sample they provided looks simple enough:
Code:
<?php
define("GREETING","Hello you! How are you today?");
echo constant("GREETING");
?>
But here are my questions:
1. Where do I put the define?
2. How do I determine what the define's value should be?
I think that in order to understand what the define's value should be, I need to understand the logic behind the output (i.e. where will it appear so I can figure out what its supposed to say? what purpose is it serving?)