So what happens or where do we go? Do we join loved ones, and ancestors? Or how did you learn this?
I'm trying to say that the you who is talking to me right now, the ego structure, doesn't exist. So "you" don't go anywhere. The real you, which is unchanging, pure consciousness, remains the same. It was the same when "you" were born and the same when "you" die.
It's like asking, what happens to water when it becomes ice or vapor? It's still fundamentally and inseparably water, but it can have the
appearance of ice or vapor. We can even strongly identify with it as either form. But at the end of the day its essence is unchanged.
My example relates to matter but try to understand this from a consciousness perspective. Nothing is born and nothing dies. It's all an appearance.
A better example might be the waves of the ocean. There are small waves, big waves, waves that last for minutes and others that last for milleseconds. No matter what kind of wave arises, it always dissolves back into the fundamental ground of reality: the ocean. Our individuated natures are like the waves. When we identify with ourselves strongly
as waves through ego, then it looks like, "Hey! Look at me! I'm a me! I'm a big wave! So what happens to me when I die?"
Well, nothing happens. You dissolve back into the ground reality that you were always part of.
When you are alive, you are an individuated form of the Brahman. You are Brahman-As-You, totally personified. You are Brahman experiencing Itself by shining the light of consciousness through a human-mind body, just as the ocean funnels water into a momentary, individuated wave. The individuation is a real experience. So you are real, I am real, every unique differentiation in what we call reality is "real", but it all arises from the same source. It's not enough to say "we are all One", because although it's true, it also denies the human level experience. Brahman came through as you, it "wants" (for lack of a better word) to be you. It wants to play as your unique chord. So people who abdicate themselves to Oneness are missing a big piece of their important existence.
There is no experience level with Brahman. Brahman is already perfect and unchanging. A mind-body needs to exist for experience to even happen. Brahman projects through a human mind-body and then that mind-body has the capacity to experience Brahman, but only through itself. It's why I can't experience lief as a dog, or a tree, or an insect. We are "All One" which people are fond of saying, but it's why Oneness-As-Me can't experience Oneness-As-You, even though we both arise from the same source, the same ocean.
The mind-body then projects the further additional level of the ego, which says, "I'm me! I'm this, and this, and that." There are many discursive layers of the ego that try to assert its realness, but ego is a pure hologram. It serves a function to help the mind-body navigate a material world, but it is substanceless. The ego arises and dissolves even while you're alive, if you're observant. Where is it when you're asleep? Or in certain altered states? Or when you have a concussion? Or when you're in fight or flight mode? Or a coma?
How did I learn this? Years and years of meditation, consciousness observation, inner inquiry, and surrender. Almost dying a bunch of times kind of cut through it too. If you want to study a system that can sort of point you to it (but not give it to you, since nothing can), look into Advaita.