Every soul is (in existence) present like an atom in Rooh-i-Baseet. When Allah desires to bring into being any soul He fixes His life enkindling look in it, through whose effect this spiritual atom becoming longer like the shape of a ray (or in the words of the Qur’an, shadow) starts descending towards Alam Asfal, (neither most world) but unlike water the top of this spiritual atom remains stationary at its own place in Rooh-i-Baseet. After passing Rooh-i-Baseet this ray enters Aql-i-Baseet and according to its capacity while absorbing capacity intelligence reaches Nafs-Baseet and takes from it, its destined share. The meaning is that here Nafs is born into it. (What is Nafs? It is unused wish).

Now this reaches Adam Baseet. Because according to the law of creation no life can be specified till it does not come against its opposite force. This is called anna(ego). Another aspect of this phenomenon is this that as the soul while passing through Aql and Nafs absorbs its properties, likewise while passing through Adam also absorbs destructive properties. If it was not the case, then whatever would have been born once would not vanish at all. Alam-i-Amr comes to an end at the end corner of Adam, that is, still its existence is hidden and is in the knowledge and will of Allah. Now this ray enters Hoo.Here it should be borne in mind that in every soul from origin to return its fate is hidden just as in the small seed of banyan tree is hidden the entire life of the giant tree being born from it.

Now, for certain, this soul will be either a dweller in hell or a dweller in paradise (hellish or heavenly). If it is hellish, then some particular place is assigned to it in any of the stratum of Alam-i-Naasoot where it has to stay till the day of resurrection after the material journey. If it is heavenly then it is assigned some particular paradise in any world or stratum of the worlds of paradise. This very paradise is called Maqaam-i-Mahmood (exalted position) of this soul.

In short, after completing the journey of Aalam-i-Amr this soul while passing through the worlds of Rooh-i-Alam-i-meesal reaches its exalted position(or if it is hellish then to place of return in Alam-i-Nasoot). Here it stays for a while so that it becomes familiar with the place. In fact it is given life at this place which is rightly called spiritual existence. Now starting from the exalted position and covering through the remaining worlds and passing through Alam-i-Nasoot enters ether which is the finest and last limit of matter.
From ether while absorbing fine senses and other material properties and strength according to its capacity goes to the sun of any solar system and after obtaining from it life or warmth of human soul gets to the sphere where it is to take its birth. Now it is entered through the process of arrangement on any eatable thing such as fruit, corn etc., and that thing is given for eating to one who is to become its father. It is transferred from father’s spine to mother’s womb. It remains there for nine months for material formation and, then, after becoming human being is born to the material world by taking to material shape.
Now after living a life as destined goes back to its place of return or exalted place and remains there till the day of resurrection. After this Allah will deal with it as He wishes.
Here the particular point to be noted is how this ray in Rooh-i-Baseet traveling from its first tip gradually becoming thicker and thicker from fineness get to the sperm. What is sperm?
It is bacterium or the foremost and thinnest unit of material bodies which is hardly visible through microscope. This very bacterium while taking its sustenance an the womb of mother gradually becomes thicker and thicker and comes out of the womb of the mother.

(for detail pls read book)