Well look no further it’s very simple to comprehend. You only need to look at Super Mario to understand the complexities of it all.
John Pavlus created a wonderful video that visually displays what the idea of a multiverse looks like and how within we may interact with other objects. Abby Seiff explains further in her post for Popsci.com – “the 134 overlaid (Mario) playthroughs represent the manifold possibilities Mario encounters as he progresses through his world.”
Just don’t get sucked into watching the game play more than the accompanying explanation.