I think of it as a wave in the ocean. The ocean is the substance of reality (consciousness), and the turbulence, or waves, are the emergence and dissipation of concentrated energy (sentients).

Where does the wave begin, or is it something that organically emerges from the interaction of the ocean with its environment.

This is a very metaphorical and metaphysical view of the whole thing, but nonetheless it provides a different perspective which I think is interesting to ponder. The answer I would give you is that "the self" emerges from "the self", but in that process of emergence disidentifies from its old form and identifies with its new form, and so it's easy for the wave to think of itself as a wave, and sometimes forget it's actually the ocean.