It's Like a Plate of Spaghetti Everywhere
Imagine you have a plate of spaghetti, but instead of just a plate, you have a whole multiverse of it. That's basically what entanglement is.
When you think about one part of the spaghetti, the other part of the spaghetti instantly knows about it, even if they are on opposite sides of the plate... or the universe.
What's the deal with the plate? No it's not actually like a bunch of spaghetti...