How does the practice of creative visualization which we use to manifest what we want in life, fit in with the concept that “We are not the doer”?

You mentioned, “Right now you are at the center of the universe because infinity extends in all directions, yet someone on other side of the world is also at the center of the universe because infinity extends on all sides of him too. The fact that you appear to be at different places is a sensory artifact.” my question is what is mean by sensory artifact? And what is this phenomenon??? I didn’t understand…