Paypal Basic allows you to receive payments using Paypal. Once a user has created an order he gets a Paypal button which he has to click in order to pay. This button is available in the order confirmation page as well as on the order tracking page. It'll disappears once the order is marked as paid.
the email address of the receivers account
if set to production you can start earning real money. Otherwise the sandbox mode is used. Make sure you entered a sandbox receiver.