No, Samsung does not have access to user banking details.
To pay, open Samsung Pay, select the desired card and finalize the payment with your fingerprint, iris or PIN. Then move your device closer to the NFC reader to complete the transaction.
Activation may take up to 10 minutes. If the time is up, remove and re-register the card, or contact the card issuer.
Samsung Pay is free of charge, but there may be costs related to connecting to the Internet, depending on your carrier.