The order page displays your current order and each image which you added to the order will be listed along with the details of the order such as the print size, quantity, cost etc. This page will be displayed whenever an item is added or removed from the order but you can also displayed this page by clicking on the 'Current Order' link at the top right of any of the pages.
Once all the required items have been added to the order, pressing the Process Order...' button will display the 'Customer Details' page where your address details etc. can be entered.