On other shows we talked about wiring in ceiling fans -- today we dealt simply with how to attach it to the ceiling so that it does not come down on top of the bed like a giant blender.
You cannot just attach it to the ceiling drywall.
You cannot just attach it to a simple electrical box in the attic.
You must have something structural that will definitely carry the weight and vibration of this fan.
If you have access to the attic, you could install a 2x4 between the joists that would allow for long and strong screws to carry the weight from the motor housing of the fan through the electrical box.
But they actually make ceiling fan structural bars to do this job neatly. These gadgets can actually be inserted through the hole below and hand tightened into place without getting into the attic -- a turning threaded spreader bar will dig spikes into the two ceiling joists as you tighten.
Then a suspension arrangement off of the bar carries the weight of the fan.
Air Sealing
If this is an insulated ceiling, make sure that there is still insulation over your installation when you are done, and also make sure that the installation is finished in an air tight fashion to keep hot moist air from getting into the insulated roof space. With moist air flow, the equivalent of 10 pounds of ice can go though one electrical box over the course of a Canadian winter. If you can't do it from above, then seal the cover plate from below.