I condition it with whatever conditioner you choose, and then let it set for a minimum of 30 minutes, preferably a couple of hours, just to make sure that the conditioner has gotten rid of all the chlorine. (It says it's instant, but I don't trust that completely.) You really don't need to age it unless you're doing that instead of using the conditioner...which I really wouldn't recommend if you're on city water, since the chloramines that are in most city water will never evaporate, and the water won't be safe without conditioner.
If you're going for the 30 minutes, I'd put the water in at whatever temp matches your tanks. If you're going to age it for a few hours, but it in a bit warmer, and let it cool.
I hope that helps!! :D