If a costumer buys a product you want him to be redirected to the "return url" or "page after successful payment". This page confirms that the product has been purchased and that it will be delivered.
You can set the URL of the page yourself if you go to "Manage payment buttons" and click on the product in question. Under the heading "Delivery" you can enter the URL of the "page after successful payment".
Something still unclear?
Whenever you still have any difficulties or questions feel free to start a chat (right blue button) or contact us at firstname.lastname@example.org.