The “world” of Spirit exists “behind” or “beneath” the world of matter in which our senses operate. You can think of the Spirit world as the ground from which the flower of the universe springs. Notice the present tense there. This is an ongoing process, not an event in the distant past.
In the world of Spirit, there is nothing but Spirit. There is no space or time or anything else but a singular essence—Spirit, or Consciousness. There is no “other” there, which is why this world exists (and perhaps others). Spirit animates matter, producing life, and through these life forms it is able to interact with other beings. There is a “piece” of this original Spirit in each living (and non-living) thing, and this Spirit is able to express its nature through each creature to varying degrees.
So, what happens after we die? The Spirit that animated our bodies still exists, and carries our life experiences with it. Spirit learns about life by living it—all of it—Itself. Why? One reason is because the basic characteristic of Spirit is Love, and Spirit wants an “other” to share its Love. Where else does Oneness produce an “other” but from itself, on some pretend level of reality (if you will)? The cause of this creation is Love, which makes Love the essence of existence.
First there was Spirit. This Spirit was unified; it was One. Its nature was to Love, and it had no “other” to love, so it nudged…and light was born in the explosion that brought forth matter and the present Universe. Through light, Spirit animates matter and is able to live and interact with other beings (whom it also animates).
It’s impossible for nothing to exist. Something always exists and so, since Love is the essence of existence, we can say that Love is eternal.