I'm imagining it to be like our universe just bigger and better, where everyone who succeeds will get at least one planet (the smallest one being 10 times the earth confirmed). Depending on the rank, I imagine some even having their own galaxies. The higher the rank the more of paradise is "unlocked" (for 'space' travel) for you without restriction. Firdaus is the highest rank right? So that's the ultimate unlocking of everything, it's the creme de la creme: the biggest and most luxurious where the lucky ones get multiple galaxies. Anybody below this rank needs explicit permission from its inhabitants before they're allowed to visit. It's invitation only! There would be utility planets for markets, meet ups and stuff. As for hell I'm just picturing one giant black hole or an enormous burning star. May we be protected from it. Share your imaginations!