Methods given in the book are yoga methods which I practiced myself. If you buy the book and do not get any benefit from it, send me an email and I will refund your money.
As far as linking the buddhi organ to the third eye, that is happening already anytime you focus forward in the head. As soon as your attention moves forward into the frontal lobe of the brain, the buddhi organ gets linked into the third eye and into the five sensual organs.
So what you need to do is to realise how this is taking place. Usually we are using these psychic apparatus and we take it for granted so we do not observe how it is going on. What yogis do to understand this and to observe it in great detail, is to practice the 5th step of yoga which is called pratyahar, which means to pull in the sensual energies. When doing that there is an impulsive force which pulls against one's will power and one studies what happens when one releases one grasp on the energies and they fly forward and outward.
This study gives one some idea of how the buddhi is fused into the third eye or the senses.
You are not going to learn all of this overnight. Like everything else, it will take some time for you to get this under your skin.