The Audit can be a good thing though. Lets say you submit your application (step 2 outlined by Nishant), and it gets accepted. Then you study 6 months then go to pay for the test (step 3). At this time, you get audited, which isn't a big deal because you were honest and transparent on your application and history. After your audit comes back as successful, your time is then extended AN ADDITIONAL year. More study time!!
Back to you question though, Nishant is right, you need to get your application approved before you have the opportunity to pay for the exam.