... and assuming there is no water in the
oil, or
oil in the water, the classic "first step" in tackling an overheating situation is to start the car up and see if the thermostat opens and the fans come on. If it does, and they do, then you have to try and recreate the overheat condition. If you can, then either too much heat is going in to the water/coolant, or not enough heat is coming out. Considering how new your car is, it's almost a sure thing that's it's the former.