Remember, your bird will be captive bred and won't have any idea how to survive in the wild. If you lose it you will certainly be sentencing it to a slow death by starvation if you fail to find it in time. The Raptor Trust recommends a minimum aviary size of 12' x 8' fitted out with perches and a nest box. The walls, mesh and flooring should be made of the appropriate materials. One absolute requirement is that no chicken wire or any other bare metal mesh must be used.
Birds can suffer severe injuries by flying into such materials.
Again, this must be built and fully fitted out before you get your bird. They need to be fed, trained, exercised and kept in clean conditions. Roughly speaking, looking after a Bird of Prey takes as much time and effort as tending a pony. All Birds of Prey need regular exercise but they soon become so used to a single piece of land that you can have real problems it you ever need to fly somewhere else. Ideally, you should have five or six different places to fly with the Landowner's consent.