Hi everyone, I am kinda new to this kinda stuff(For I am a foreign student planning to go to college in the U.S.) so I would like to know some stuff about the SAT, first about the the preparation; I don’t know how to prepare for this, and 2nd, the score I mean how low is a score of 800 and how high is 2400? could someone please help me!

without any specific practice for sat i scored above 1450 in diagnostic test…math 510 C.R 500 and writing 440(excluding essay)…i am foreign student and english is my second language…i have more than 3 month for sat preparation..how much can i improve and what is minimum requirement for admission in colleges of USA???
i just finished my 12th class.