Adding airtime is a breeze. Simply press the 'Menu' key on your activated NET10 phone and select the 'Prepaid' menu. Next, select the 'Redeem' airtime option, enter the NET10 Refill Card PIN number and press the 'OK' key. Presto. Airtime will be sent to your NET10 phone and you will be notified by a free text message when the time has been added. And don't forget to hold on to your NET10 Refill Card until you've received confirmation that your minutes have been added.