Overview from the press release:
Themed to Disney fantasy, the new Disney hotel will be located inside the Park. The hotel will rise above and around the magical springs that serve as the core of the new themed port’s story. Park-facing rooms will provide beautiful views of the port’s majestic landscape, affording Guests a magical experience that can only be had at this hotel. The Disney hotel will offer 475 deluxe-type and luxury-type guest rooms, with the latter providing the finest accommodations in Tokyo Disney Resort. A merchandise shop that helps share the story of the magical springs will be found on the hotel’s first floor, facing the Park.
For more information here is the initial press release