1) From the scientific pov, i dont believe we're ever gonna explain these questions you did, because its not science's business to answer that
2) From a philosophical pov, I would say thats is not the business of philosophy to inquire how "the source" really works or where we can find "the source". The philosophy can only say: "the source is this or that" and "Following the logic the properties of the source are this and that".
From a non-dualistic pov (that I believe is real): the source can be accessed by us, not through rationality, but through our internal experience. But in the non-dualistic pov, there is no difference between subject and object, both are the same thing. The sentence "x knows y" is dualistic, but in the non-dualism there is no "x" or "y", only "knows". That means when someone has a non-dualistic experience, this person is not having an experience as if this person is something different from that experience. That means the experience is the only reality and nothing more. The subject is not real per se, nor is the object, both are only part of something called experience. And what you called "source" is the experience, the only thing that is really real.