Zen Cart is built on a system called ‘overrides.’ When you have worked hard on customizing your site you do not want to lose all that work when a new version or cart update comes along. So, follow the guide for creating a custom template and it will ‘override’ the stock template.

Read, comprehend and apply these threads and you will be blessed by the Zen Cart magic. Your new custom template folder should only contain files that have been edited for your site. Copy the files from template_default, edit them, and make sure they are in the correct ’my_custom_template’ folder.

The Wiki is a great place to start. However, since the forum experienced an emergency reload, many of links have not been updated. Be patient.

http://www.zen-cart.com/wiki/index.p..._-_Customizing
http://www.zen-cart.com/wiki/index.p...on_-_Templates
http://www.zen-cart.com/wiki/index.p..._API_Overrides
http://www.zen-cart.com/wiki/index.php/Basic_Checklist

From the previous forum by NetworkDad is my favorite.

http://www.zen-cart.com/forum/showthread.php?t=7263

Good Luck