Sat will be a 3 hours exam. Sat will comprise verbal and quant for which you will get 3 hours on totality. Essay is optional for which you get additional 50 minute. Sat verbal will comprise of writing section testing your grammar. Next verbal section is reading comprehension/passage. Questions will be asked based on the passage. Passages can be from any domain. Math has 2 sections. 1 is without calculator and other is with calculator. Math topics would range from geometry,trigonometry, ratio,etc which you may have done/pursuing in school/college.