It appears you have correctly set up that page with our JS example to embed your E-junkie-generated thank-you page content (including download links) in an iframe within your page.
Note this will only work when the buyer is redirected to your page after checkout or via one of the [%thankyou_link%] URLs we send to them in a thank-you email message. Otherwise, viewing your page directly without being redirected there via one of our URLs would only display our generic thank-you information, "The payment processor has not yet informed us about your payment...etc."
You can test this by clicking one of the Transaction IDs in your E-junkie Transaction Log, which is linked to the thank-you page URL we generated for that buyer.