Log in to your UltraCart account and navigate to Configuration > Screen Branding > Screen Tab > Select Theme. If you are using Single Page Checkout you only need to edit one screen. Once selected, go to the footer section at the bottom of the page and paste your AdRoll Pixel immediately before the closing </body> tag. If you are using Multiple Page Checkout, simply select the option to copy to multiple pages or repeat the placement process for each screen of your checkout.