Imagine looking at a reactangle that gets thinner and thinner until it's just a straight line. And then imagine that you shift your point of view, to see that a

Imagine looking at a reactangle that gets thinner and thinner until it's just a straight line. And then imagine that you shift your point of view, to see that actually that line has depth, and from the side the "line" is actually a new rectangle. It's not as though the new rectangle suddenly appeared: the new rectangle was always there as one face on what you now realise was a cuboid. However, from your original perspective you couldn't see that face. This example is not exactly the same as what's described by CCC: I don't know if you could describe each universe as having "new dimensions", and instead of shrinking, each universe is stretching out to infinity, but the "change of perspective" part is a useful analogy I think: each universe only looks like it starts at a single point if you observe it from the the right frame of reference. If you could somehow observe our big-bang from the reference frame of the prior universe it would be indistinguishable from an infinitely spread-out empty universe. According to CCC (AIUI), all of the infinitely many future universes have already started, but each universe will end before even an instant of time has elapsed for the next universe: that is, "time" as measured in one universe is on an entirely different scale from "time" in another universe.