This now seems an entirely different question. Are you asking how anything in fact comes to exist? What causes being? Why something and not nothing?
In my Peircean approach to that, individuation is symmetry breaking. The story, being developmental, is triadic. You need the three categories of a vague potential, an emergent regularity of habit or law, and then the third thing of a resulting world of actualised particulars or real possibilities.
So possibility divides into the unformed or vague and the formed or lawfully shaped. The vague state is a true everythingness that is a nothingness in its pure symmetry or indeterminacy. But as that vagueness is broken by organising principles, then you have crisp alternatives where events have either happened or they have not. Counterfactuality exists.
Thus talking about an actual world - as a container - is talking about a state of habitual emergent order in which local events or entities now can be said to concretely exist in a counterfactual sense. It is now the case they might not have existed - as either the global laws of nature, or simple material accidents, might have determined they do not.
So in our world at least, the possibility of rivers flowing uphill is not an actuality due to natural laws. And then the possibility of this river forking there rather than here is a possibility denied merely by some material accident of history. It is impossible not in the formal sense, but in the sense of a material fact.
Thus actuality itself is an irreducibly complex state - hylomorphic. And possibility is a word we use that in fact reflects the various elements it takes to be actualised. In Peircean jargon, you need the hierarchical organisation, the triad, of firstness, secondness and thirdness. You need pure vague potential, then the emergent habits that organise it into a definite state of being which then becomes a world of actual localised events.
In the beginning, anything is possible and nothing is actual. After the symmetry is broken, only some things are possible (due to laws and history). The rest are now possible in only the apophatic or suppressed sense of the counterfactual might have been. There is now a definite fact of the matter that they don't exist (either due to law or history).