When should I take SAT 1?

[Scafalon40]

I'm in my second and final year of A-levels and was wondering whether I should take SAT1 in January next year or afterwards. I've heard that you need to take SAT 1 in your AS, is that true?
And should I take SAT subjects?
I don't have a clue as to what to do, please help

 

[anwar2400]

which universities/course are you applying for? (do they need SAT? If so then which SAT2 subjects)