What do you mean ‘creating a multiverse’? Usually, this is created for us, and sits above the material world like a bigger, better, more adventurous version of the setting we have to come up with from scratch.
I love the planes as expressed throughout D&Ds history. They are really fleshed out by now, with their own setting best exemplified in 2nd eds Planescape. I’ve always found it odd that campaigns are expected to be made up from scratch (or bought off the shelf) but that the planes are the ultimate destination, and that one DMs planes will be much like another’s. At the same time as all bets are off as far as fantastic locations are concerned, the big story becomes more straight jacketed by its supplements.
Until now. Just as in Chapter 1, it’s now the default for a DM/group to make decisions about their multiverse. Plenty of examples here, including wheels, trees and axis, and others. The planes are described briefly, but they’re all here, in a gazetteer format. Each location has a quick optional rule to help enforce its otherworldliness, and the logistics of travel and survival are addressed. Basically, you get a mini Manual of the Planes inserted into your DMG.
I love it. None of it is particularly new, but it’s all to hand and distilled into its most gameable and easy to digest chunks. The book is at pains to note the sheer optionality of the work. Pick and choose as you feel, and when you feel. You won’t be ‘wrong’. Sure, it doesn’t go into massive detail, but it doesn’t need to. If you like what you see here, then the older sourcebooks will fill in the gaps, and they’re on D&D Classics on pdf.
That’s the end of part one of the new DMG. If you follow it to the letter, you’ve just created your setting, including the multiverse it sits in. Not bad for 68 pages.