The Skins page provides a central location to manage Skins and Containers that have been uploaded to your portal. In order to access this management, when logged in as portal administrator, click Skins in the menu. It will be possible for you to have a preview of all the skins and the containers among which you can choose the appearance of your portal. In order to view the preview you will simply need to select one of the fields, Skins or Containers, in the drop down list, and the page will automatically update with the new images.
By clicking Preview under every image another window, which represents a page of the portal  modified with the selected skin or container, will be displayed. In order to proceed with the modification click on Apply under the selected image.