Insert your debit card in and out of the marked credit and debit card slot. A picture of a card is typically next to the slot, indicating which way to slide your card in. A keypad and LCD screen are also next to the card slot.
Press "Yes" when the screen asks you if you wish to use your card as a debit card. Enter your PIN number and press "Enter." Then enter your ZIP code if the on-screen instructions request it.
Remove the gas nozzle, select your grade of gasoline and begin pumping the gas when the screen instructs you to do so.
Hang the nozzle back up when you're done, and press "Yes" on the keypad to receive a receipt or "No" if you do not wish to receive a printed receipt.