For payments in shops, you can use either pin payments by inserting the card in the POS-terminal and using your pin code to authorize the transaction or you can use the contactless payment by simply tapping the card on the POS (for payments under 25 EUR)
For online payments, you'll need to use your long 16-digit card number, the expiry date and the CVV code (3 digits) on the backside of your card.