The difficulty with explaining how ghosts and hauntings work is that we have yet to prove ghosts and unexplained phenomena, so stating any facts about it is presumptuous.
What we can do, however, is look for patterns and commonalities to come to some concept for how it all works.
Let's begin with that moment of death. What we know from near-death experiences is that when one begins the death process, they go through some common thematic voyages from tunnels, lights, meeting dead relatives, and life review. It begins with a moment of detachment from the body, yet a continued consciousness.
Here's how I like to look at it: I'm psychic. I get information from a method that does not appear to depend on the five senses or the knowledge that is already in my mind. This extends beyond my "conscious mind" which is ruled by the brain activity.
When a brain dies, the conscious mind is no longer active, but the "drifter mind" (what I like to call it) takes flight and that mind does not need the vessel of the body, its electrical, chemical, oxygenation, or other.
The "drifter mind" has a consciousness of its own, the same consciousness that leaves us when we perform astral projection. It also can see far away from body location, like in remote viewing. Now, we're talking "spirit."
As a paranormal investigator, I utilize the same tools of temperature, barometer, KII, EMF meter, etc. If ghost consciousness does not involve physical form or electrical activity as our brain does, then what form of energy is it using? When we discover this, we can detect ghosts!
Do ghosts not know they are dead? Do they get "trapped" in locations. There is absolutely no evidence of such a concept. So long as the spirit maintains a consciousness, it is not stuck anywhere.
What spirit has is something that does not need physical location to maintain. It can be anywhere, perhaps everywhere it has ever been, at the same time.
Some of these "trails" of the drifter mind could leave an imprint or repetitive "residual" haunting feature. This might also explain how as a psychometrist, I am able to read information about people by touching and object and knowing about others who touched it. Perhaps a permeating trail of residual action, thought, feeling, and more are left behind by the drifter mind. Everywhere we have been, everything we have done is still held for all time by this endless form of energy that rules the drifter mind.
This might also explain why some locations seem to hold bad feelings, good feelings, and the like. The more people that come to a memorial and feel grief over time, the more drifter minds of the living have left trials behind that our own drifter minds are able to feel on some level (our psychic self).
When I started officially seeking out paranormal investigating, it was because of a psychic read I did on a new homeowner's home that was completely accurate, but the person who lived next door and knew the past owners announced that the whole family I described (who were leaving footfalls in the hallway and sounds of a woman crying in the shower), were all still alive across town.
When we consider the consciousness that is associated with our spirit selves, we must think in terms of utilizing an energy that is against the principle of creating energy means utilizing energy. In terms of spirit, this energy is universal, replenishing and eternal.
When we figure out that form of energy that is, we can not only sense the drifter minds and prove life surpasses the physical form, but possibly communicate with no limitations.
Now, imagine talking to your uncle as he is passing on and continuing that conversation into his next incarnation as spirit self.