Please follow these steps
1. In Control panel>Account>Payment Methods click on Add New Payment Method
2. In the pop-up widow explanation of the process will appear. Click “Continue”
3. Enter your credit card details and click “Pay $1.00”
Please Note : The $1 charge is used as a pre-authorisation check on your credit card to check its valid. The amount is immediately reversed back to the credit card once pre-auth check has been completed.