The SAT is administered by a company called “The College Board”. We highly recommend you go to the College Board‘s website www.collegeboard.org and become familiar with its content. You can even register with them if you wish. You can register as a student or parent. They will then email students a “question of the day” each day to keep you practicing and send you other important information. When you register as a parent, they will send out newsletters to remind you about important test and financial aid deadlines. It is a very useful and informative site for both students and parents.
Regarding the test, it is administered several times a year, from early October to early in June. Starting 2017, they now have an August test date. Most students start the testing process in March of the Junior year, but the eager beaver students start earlier, at least in the Fall of their Junior year.
Students have to register with ‘The College Board’ to take the SAT – not with their HS or any SAT Prep company. There is a fee for taking the test, but it can be waived for low income students. Inquire at your school’s guidance or counseling office to get this waiver.