Once you are at the Manage Services page for your Website Builder, you will see a summery of your service.
One the left-hand side of the screen, you will see the name of the service and your current plan. Below this information, you will see buttons to either Upgrade your plan, or Request Cancellation. To the right hand side, there will be information on your next due date, as well as your renewal price on the right of the screen.
Below this information, you will see your DNS information that is required for your new Website Builder website to be live. You will find the Log In To Site Builder button towards the center of this section. Clicking on this will launch your Website Builder.