So what is already stored in the storehouse consciousness (eighth level of consciousness) from previous lifetimes is what the first six sense consciousnesses perceive, which causes additional moments of consciousness.
The seventh consciousness (intellect) acts upon the six sense consciousnesses, leading to our perception that an external world exists (causing additional storing of consciousness for future lives).
There is actually no external world; it is only what each moment of our sense consciousnesses and intellect produce from perceiving what is in our storehouse consciousness.
Everything in the world is merely our consciousness projected outwards as perceived reality.