Basically just like the gods the angels (the Elohim) are forces and aspects of creation, the embodiment of them. Book of the Secrets of Enoch for example goes into detail how God created the world by commanding aspects of the world, specifically the solid/matter (called Adoil here) to come out of the invisible and set itself at the lowest of creation. So when the other mythologies explain how the gods or the aeons/archons created the Universe it speaks of the angels being created and told to take this certain form and state of being which subsequently make up this world. Generally where as other myths go in great detail which god did which deed the Bible treats them, that is the angels, more as a tool of God, stating God did this, occasionally mentioning the angel he sent. In the same sense you can imagine that God creates this infinite light (the Ein Soph in this case) and fractals himself through a bunch of prisms/lenses to create this realm with matter as the lowest spectrum of the light that we perceive with the Sephiroth functioning as the angels shaping the light into the form they take in the lowest form, the Malkuth
So when the Demiurge (basically Satan) created the world in gnosticism I believe its more about the world being created through the demiurge which after rebellion started not working as he should have and tempting people through egoism, materialism and hedonism which became the foundation of satanism as we know it.
However this World was not created by him but the true God, not as a Prison, but more like a sandbox or containment area. Imagine a bunch of children in range of the big red cosmic selfdestruct button on which stands "DO NOT PUSH". It would be pushed pretty much instantly, and the same would be if the drooling retards we are were to get our cosmic powers. So we are here to learn first
If you have troubles with the names we can pretty much relate the terms to other systems as they pretty much all describe the same slightly different. The Ein Soph is probably best related to the Gnostics "Monad", the endless void in which everything is together and uniform and thus nothing until it split up into everything. Its also the Singularity of the Big Bang Theory in which again, all was one in a uniform mass until things split up and create everything. I would say this is best described as pure energy or light. This is probably also the similar to the Kundalini, the energy that runs through the Chakra . The first Manifestations of this is the Kether or the crown, the first of the Sephiroth presenting will or intent. From this first thing that came forth from this energy all the rest was formed after, through the will and intent and on a personal level represents your very existence. before any knowledge, wisdom or any outside influence shaped you. The Kether, the Crown relates then to the Crown Chakra, the highest like the highest sephiroth that is Kether. This Chakra is responsible for your connection with the world and all there is, like the Kether that connects you to the Ein Soph which is the all. The Chakras in general seem to describe states or levels of conciousness which the Kaballah does describe to. In that sense you can see the the Sephiroths or Chakras as lenses or Prisms reflecting the light/energy and making from the pure white the different things all down to the matter eventually
Basically all we percrive are vibrations, the matter vibrates so fast we dont even actually touch it but just feel its effect, almost like we just see other vibrations of light in the eye. Heat too is just infrared light or when touching higher vibrations of the matter So when everything relies on vibrations what happens when there is no sun/light? Everything cools to 0°K, all movement and vibration seizes to exist and essentially nothing to perceive exist anymore So for anything to exist there must be light. Matter in that sense is just the lowest spectrum of the light. Now what is Satan? He is the ruler of the world, said to have created it even (the demiurge), he is the matter, but he also is the lightbringer, the light that creates the matter. Now God is the one that created him and the other angels, and told them what to do, which form to take etc. to create this Universe, and Satan is essentially the foundation of it. Now depending on who you ask either Lucifer has light in him himself or its that through him the light is taking his shape (you know that image of the prism that creates the rainbow? Satan would basically the prism that refracts the light to create/arrange the things that are. Originally he did so on Gods command having us live in the paradise, but ever since he rebelled the whole world got corrupted. The different Sephiroths in the Kaballah are like these prisms that let the light take its shape and colour to create our world. Similary the material world, Malkuth, gets filtered through the different conceptualizations/sephiroths upwards that we created in our mind until it reaches our intellect (Understanding and Wisdom) and our conciousness itself (Kether) and forms our worldview.
So when there is nothing left to perceive from the outside, will you be a light onto yourself or seize to exist? Are you concious? Do you have a soul?