Here is how you make use of a custom template in a listing.
Once you are on the new listing page, scroll down, pass the section where you enter the start price. The next section will be called Template: and there will be a link called Select Template. Click on this link.
A window will popup that will show you all the templates that Auctiva offers. In the list box on the left side of the screen, the third item in the list is Custom. Click on this. The page will reload and show you all the custom templates you have created. Click the Select button below the one you want to use. The page will reload again and give you a preview of the page will look like. After this has loaded, on the left side, click the button that says Save Template to Listing. This will then save the template to the listing you were creating. Now select the images you want, enter your description and other details for the listing.
Once you have entered all the details about the listing, click the Preview button at the bottom of the page to see how the listing will look on eBay with your custom template.