The most important thing is to identify where the water is coming from and stop it. If you have interior walls leaking water you're either looking for a busted pipe or a roof leak

Okay I'm not a lawyer and I haven't seen your policy but even if the water damage isn't covered, the leaks had to exist before the water damage. Insurance should cover your windows and basement leaks.

Also Google emergency flood treatment in your area. When my kitchen flooded it was a flooring company who did ours but that's bc we only needed new flooring. I imagine many other general home work type companies provide the service

You call your home insurance