This explanation has two givens. The first given is that everything in creation has consciousness. Even rocks know that they are rocks and maintain form in creation and level one consciousness in spirit. The second given is called soulstuff. Consciousness tends to build itself and gather awareness, once a certain level of self awareness is reached, the potential for the formation of a soul occurs.
So creation is an incubator for souls. Souls come from eternity(a place where everything is at once and with everything at once) ... and undergo the rule of forgetfulness to incarnate into 3d reality. By undergoing the rule of forgetfulness and incarnating into a physical universe a fledgling soul is able to experience the illusion of separation from the creator in order to develop its own individuality even further. Much comfort and support is available in eternity but little growth spiritually can be accomplished because everything is available always and you are with a loving creator and all of your friends all of the time, though there is no time there. The purpose of life is to come here and experience things that you purposed to do before you came here. By doing this over and over you gain all of experience and grow up into a master of creation. There are many things to learn along the way not the least of which is the oneness of all things ... but you can take as much time as you want by incarnating as many times as you want , so you grow at your own pace. Also no experience you ever have is lost but records are kept and there is no judgement. I hope this answers your question.