To be honest, the occult book in question is False, it has to many faults, I have been studying Occult for 20 years plus, I have worked with many. Some work, some DO NOT. In the End, Jinns and other areas are folklores, to make people frightened, to say within the religion of origin of that Country. Their are other forms of this, which is not going to be discussed. I say this, knowledge is power, but bad knowledge can led to mental illness, and cause lots of problems in your life. So study them, by all means, has my elders of my coven say, "Only believe it, when you see it," He did say something else, which is secret. So keep learning, and keep a open mind. And also think clear, do not believe in to much. Witchcraft is vast subject, and has lots spells and other materials you should study. Basics first, even be on your own, write journals, and dream journals. Do a spell, see it out come. Write about it, if it worked or not, still write. Oh, yes, read about myths/Folklores, and history. There are entities out there. This world has many secrets.
Dark blessings....good luck on your search.