Adding a payment method to your account:
Add a model to your cart
Click view cart
Under Payment Method do the following:
Click pay with New Credit or Debit Card to pay with for your purchase with the the accepted forms of payment listed
Click PayPal to login which will link your PayPal account and allow you to purchase via Paypal
Changing your payment method:
Add an item to your cart
Click View Cart
Click change current payment method by clicking the change payment method (highlighed in blue) option
Complete the required fields with your payment information
You can save this to your account or as your default payment method by checking the options at the bottom of the page