> Even if everything is relative and space is infinite, there aren't any
> bounds like the start or end of space. How can be this space in
> nothing?

If you agree that space is infinite (that it is unbounded), then the universe by definition cannot be ***in*** anything.

> It is supposed to be in something, forming something like atoms are
> forming complex structures.

Why is it *supposed* to be in something? It is completely foreign to me how someone could even begin to propose such a notion.

> But if it's in something then where is this something? So that would
> be infinite recursion and if this recursion ends somewhere it would be
> again nothing.

Again, if it (the universe) is within something else, then the universe is by definition not infinite and not bounded, conflicting with your first premise.

> Do we exist? If we do, then where?

I'm not sure how you jumped from the universe to people, but either way, as with anything else in the universe position is determined by relations. *"To the left of the car"*, *"X feet above sea level"*, *"Y meters in front of me"*, etc. There are an infinite ways to describe one's position and infinite degrees of accuracy for each description, so just pick one...