Contact the admissions office of the particular university where you are applying. They will be able to tell you if you need to take the test in order to be accepted to the college. They will also schedule your test for you if you're required to take it.
Take the online practice tests. There is a short version and a full version of the practice test that you can take, as well as downloadable practice tests in .pdf format at a website set up by the Cambridge assessment team. You will find a link in the Resources section below.
Show up to the test site on the appointed day with nothing extra. No helps, such as calculators or dictionaries, are allowed while taking the test. Administrators will provide you with all necessary materials in order to take the test.
Contact the college for test results afterward. TSA results are not issued directly to the candidate. Each university has differing policies on how it uses and applies the test results. Make sure to follow up with the college you're applying to for full details.