where is the radiator located and where do i put water

First off, don't put water in the radiator, use coolant approved for your car. Second, if your fan remains on after you shut off the car that is normal, it's staying on because it detects that the engine needs to still be cooled. If it doesn't shut off after about 10 minutes then it might need to be checked out. There should be a reservoir that has a line that the coolant, most likely a pinkish color, should be at.