1: Sign up for a Global Iris account to receive your merchant account information and secret key.
2: Email Global Iris and tell them to set the response/callback url for your account to the 'checkout/iris.php' file in your installation. Give them the FULL url:
Example:
http://www.example.com/checkout/iris.php (Or https if over SSL)
(Note. This cannot be currently done in your Global Iris control panel).
3: Enter applicable details in your Maian Cart admin area:
Catalogue > Payment Methods > Global Iris
The callback url for all operations is:
http://www.example.com/checkout/iris.php
https://www.example.com/checkout/iris.php (SSL)
Where 'example.com' is your own domain.
Global Iris do have a test system and will be more than happy to set up a test account for you. Contact them to set up the test account. This will involve signing and returning some documentation. Their service is fast and efficient.