well if your somewhere that gets cold this time of year i wouldn't recommend water, use 50/50 antifreeze coolant
but if its been sitting long enough to not be "hot" then pour it straight in the radiator, but if its still "hot" where you wouldn't be able to take the radiator cap off then pour it in the radiator overflow tank, if you don't know where it is then its a tank with a small ribber hose that goes to the radiator right under the radiator cap
