As if on cue, Stephen Strange happened to be walking out of a nearby portal.
"Hello, Bruce. Welcome back to New York." The doctor calmly moved closer, the red cape lifting up one corner into what seemed like an awkward wave. Strange appeared to briefly debate how he should approach this topic, and decided on his usual honest but blunt approach. If anyone was going to understand the complexities of alternate dimensions, it would be someone like Dr. Banner, who was holding several PhDs. "I need you to remain calm. I'm here to tell you that you've splintered off into a parallel universe, a timeline that diverged before Thanos came to Earth. I know it sounds far fetched. Um. Here. You might want to read this."
And, wait for it, here it comes....that's right...the color printed pamphlet entitled You, Other You, & the Multiverse was being held out to Bruce. It's printed on glossy paper, and is very professional looking. On the back of it, in teeny tiny print, it says: Printed at Stark Industries with eco-friendly resources on 100% recycled paper.