Earth X - can someone explain?

I'm looking over the first issue, I'm reading the synopsis on Wikipedia - and I don't get it. Other than being a Marvel version of Kingdom Come, it looks like a lot got left on the cutting room floor ie. editorial decisions.

what don't you get about it?

the whole series was basically just an examination of the evolution of mankind within the marvel context. it re-imagined the roles of several known superheroes in a world where everyone had superpowers, and gave quite interesting insights into the minds and origins of several superheroes. whether that has any basis in the 616 remains to be seen.

there were also celestials and a galactus and such. i never read past earth x, so i dont know what universe and paradise x were all about. more of the same, perhaps?

Personally I would not recommend reading more than Earth X.

When is it that the Celestials show up?

end of earth x, issues nine and on. they and their machinations are mentioned heavily throughout the entire series, however.