Hi John,
First and foremost, good luck on your journey. The 35 hours are required for course study, but beyond that no other exams are required before you can take the exam. As Elena has recommended, best practice would be to take as many practice quizzes or exams as you can in preparation for the real thing. This will limit the amount of possible retakes you will have to perform before passing. It will cost you $675 to take the PMP exam and you are only allowed 3 attempts within the year before being forced to repay. Prepare proactively!
Hope this helps.