>>40675798
It's what >>40675896 said: through lineage, slow learning during life, or also through sudden experiences
You can try to join on some esoteric group like the Rosicrucian Order, or a spiritualist group like the Kardecists
The problem is knowing if they are legit, I don't trust Thelemic or Chaos groups personally

The root of everything is the Initiation, if done right the person starts noticing some things they never noticed before
The problem is that the new reality might be too overwhelming, and cause psychological disorders or "poltergeist effects"
Having someone to guide you is important, so you have spiritual protection and don't interpret everything wrongly