In order for you to become CPA you have to find out if you are eligible for it. Each state in US has different CPA exam governed by NASBA. And you can choose one specific exam such as CPA, CFA and others depending on specialization. Your certification allows you to work for US based firm in one of the state or more depending on NASBA certification credits.
You have to check the eligibility before you apply. After application, you have to give testing in prometric centers. The cost will vary depending on the CPA or CFA selection. And you have to give exam in selected months when the testing and grading is done. Some months may not be available for testing and grading.
There are plenty of exam guide available online where you can read about how to pass exams, type of tests and most frequently asked question etc. You may have to also officially check the website. Instructions will be different for both US based CPA candidates and International CPA candidates.