After you have installed the extension on your server according to the instructions for Default Theme, follow the steps below in order to integrate the extension with your Custom Theme.
Step 1. Copy layout and template folders
Upload the "layout" and "template" folders from the extension package using an FTP client.
Community Edition: from app/design/frontend/base/default folder to app/design/frontend/base/your_theme folder.
Enterprise Edition: from app/design/frontend/enterprise/default folder to app/design/frontend/enterprise/your_theme folder.
Step 2. Copy css and images folders
Upload the "css" and "images" folders from the extension package to your server using an FTP client.
All Editions: from skin/frontend/base/default folder to skin/frontend/base/your_theme folder.