There are several different statements used to define Parallel Universes.
The first is based on a theory that observable Universe is a part of a much larger Universe, comprised of an infinite number of Universes. Each Universe is spatially separated enough within its own bubble such that someone in one Universe would never be able to observe a different Universe. In this model, it would be very unlikely that there would be another “you” contained within a different given Universe bubble.
As this Universe would be infinite, however, given an infinite amount of time that probability goes to one. In fact, there would be an infinite number of you!
Another way that Parallel Universes are thought of is based on the “many worlds” interpretation. This is built on the premise that, for every random choice made, Universe will split into two Universes, with each one having a different outcome.
This doesn’t apply to everyday choices of flipping a coin to get heads or tails, but at a Quantum Mechanical level.
P.S. You get everything. Every possible result. You just know one and the other ‘you’ knows the other. But only if you exist in that Parallel Universe!