Follow the steps below, and click on each of the 5 images to enlarge:

Step 1: Click LOG IN on top right

Step 2: Enter your credentials

Step 3: Once logged in, go to  Manage Account>Payments and you can make a payment, view your order history (invoice), payment history and payment methods.

Step 4: You will see Open Bills (current charges through invoicing date), and click the button on the bottom left, and click the NEXT button.

Step 5: You will input any information not auto-filled, and enter your credit card info (and CVV), and click SUBMIT ORDER.