how to fill the water in a corsair

Solution
You don't. They are closed loop coolers. They aren't supposed to need any liquids during the warranty period. Any sort of opening would void the warranty.
Can you elaborate on what you are trying to do?

A Corsair all-in-one cooler is not really designed to be refilled. They come sealed from the factory with coolant designed for the life of the device.

If it is empty for whatever reason the only way I know to fill one without drilling holes in it is to take the pump apart and fill it from there, then resealing the pump.