They contact you. Usually, well when DCAs handled the exams they would send the notice of examination at the latest 4 days before the exam. If you didn't hear anything on that thursday before the exam, you had to go downtown to get a notice of examination card. Since the MTA is handling their own exams I have no idea how things are going to work. But in any case give 180 livingston a call three days before the exam if you don't hear anything.