Buying Mock Exam

Hi there, I would like to find out how the purchased for the CFAI Mock exam is made. When we login to the TESTTRAC site, we are supposed to selec the exam type we wish to take. I am planning to buy the 2 mock exams for $100, but I’m not sure how the payment is made. It says that the exam will begin once we click on the exam name. And I’m kinda wondering when or how we have to make the payment or enter the payment details. Can those who have taken the mock give some guidance please? Thanks!

Choose the 100$ for 2 mocks. It will take you to a screen to pay with your credit card. After paying , it will send you back to the testrac main page. Choose *Mock exam in the top where you can drop down, and you should see Mock 1 and mOck 2 (Paid). Once you click on that, it will start

THanks!