Sazh looked once more, still waiting a few moments. It looked like at least MOST of the conflict going on was dispersed (perhaps not all entirely by Sazh's hand), aside from that cynical girl who was laughing at some other lady off to the side. Wait, now that woman next to the flaming person was flying, too? No, focus. You came here to tell things, so tell the things.
"Okay, if we're all mostly settled down..." Sazh spoke out, before beginning to speak with intent, yet caution. "For starters, this whole world you are in right now is a sort of... mash-up, of parts of many other worlds. Now, all of us here, along with some others, have each been taken from your respective places by the-... God-like being who created this place, called the Viewer."
Sazh paused for a moment, before continuing on, "Bear with me here... the Viewer has brought us here to take part in 21 different trials, over 21 days. Whoever completes all of these trials, gets to make any one wish, exactly as you imagine it. But, whether you want to compete or not, you'll be stuck here until the span of all the trials is completed." Sazh stopped again for several seconds, judging everyone's reactions, and then tacked on, "Yeah, I know it might sound ridiculous, but that's how I heard it! Either way, we're all kinda trapped here, so..."
Sazh scratched his head. Now what-? Oh, right, the city and the hotel and all that. "And, uh, we've got a big city over there, with a neat-lookin' hotel and all that. We've got, like, uh, 3 hours before the trials begin, so if you wanna rest up or prepare anything, now would be the time! Oh, and whatever you do, don't die. Dying is really bad." Hopefully that covered everything, despite how hasty it was.