Hi,
Please note that the credit card plugin is an offline payment method. It supposes that you have access to a payment terminal, provided by your bank, which allows you to process the payment with the information of the credit card entered by the customer, without his credit card.
In most cases, you'll rather want to use another payment plugin, like PayPal Pro, or Authorize.net in AIM mode to offer the credit card form during the checkout. That way, the payment will happen automatically at the end of the checkout, as is the case with the PayPal plugin.