[ 1 ] Once you are on the "Add Credit/Debit Card Payment Screen" you will just need to fill in the required areas to enter your card of choice. Once you have completed these areas, you will need to click on the "Next" button on the bottom right of the screen. From there, allow Coinbase the validate your card. Once the validation is complete, your card will be added to your Coinbase wallet and ready for you to use to purchase Bitcoins with!