With this page, you can enter the information that PayPal needs to transfer the funds into your account.
First is the email address that you want funds to be directed to. Or you can enter the id that PayPal has assigned to your account if you would prefer not to use an email account.
Next is the url you want the customer to go to after they pay for the product. Perhaps a link to the download for a digital item or a thank you for payment page. You can also have PayPal post the data of the transaction to the page.
Next is the location of your IPN script that is on the backend of your website. It is a script that will add the order to your database.
Another link that can be added is a url for a page for cancelled transactions. This could be page to try to convince them to buy or your home page.
You can also add text to the button on PayPal's site
Finally you can set the language of the PayPal payment page.