I have been working on this topic a bit more recently. It is generally a topic that attracts more and more attention. If I assume that energy is not destructible, but only changeable (everything is made of energy, just like we living beings, spirits are a form of energy), I do not ask whether I 'believe' it, but how I deal with it.
(Who knows, does not need to believe) This is generally valid
There are people around the world who work as a medium and bring us closer to this dimension, so I think it is important to keep the mind open .
The first book in this direction I read was from James Van Praagh 'ghosts are among us' (To collect some information)
There are several possibilities to approach this dimension.
Do not forget: there are many energies, the living and the dead, which you must be aware of, because not all of them do well. The protection from unwanted energies is completely in your hands.
Depending on the extent of the ability you already achieved to capture and control energies, you can settle/focus nearly on everything