In SBI Bill Desk online payment you have to follow three steps.
In first step you have to fill the payment details. You have to enter 16 digit SBI card number, email id, phone number and the amount you would like to pay. And choose the card type whether you will pay by debit card or by net banking. And click on pay button.
You have to confirm the payment by entering your authentication details.
And then you will receive an online transaction confirmation and a transaction reference number.