A spot next to most windows will work fine for your variegated Monstera. If the window is very large and gets a lot of afternoon sun, then you might want to consider placing the plant a few feet away from it or using a sheer curtain to offer some protection.
As for temperature, the most important thing to remember is that this is a tropical plant, and a relatively fragile one at that. It doesn’t like the cold and will probably stop growing entirely if you let things drop below 59°F.
The easiest ways to figure out whether your Monstera Variegata is thirsty are to stick your finger in the soil mix or to lift the pot to feel how much it weighs (although the latter may not be the most practical method if your plant is already huge).
If the soil feels humid or the pot feels heavy, it isn’t time to water yet. Wait until the top of the soil has dried out or the pot’s weight has gone down.
As for humidity, this again is one of those cases where I personally wouldn’t be too concerned about the whole thing if this was a normal Monstera deliciosa—but given the variegated Monstera’s price tag and slightly more fragile nature, it’s something to keep a close eye on.