Okay kiddo, let me explain the No Wandering Domain Theorem in a way that you can easily understand. Imagine you have a group of little ants walking around inside a jar. The jar has a certain shape, and the ants can climb up and down the sides and the lid.
Now, let's say you put a drop of honey in one spot in the jar. The ants will start moving towards the honey, because it smells yummy! But, if you keep shaking the jar or moving it around, the ants won't be able to stay on track towards the honey. They'll keep getting bumped around and wandering all over the place.
In math, we have something called a function that tells us how to transform one set of numbers into another set. Just like the jar has a shape that affects how the ants move, the function's "shape" can affect how it changes numbers. Now, the No Wandering Domain Theorem tells us that if there's a certain kind of shape in the function, then the numbers will "wander" all over the place, just like the ants in the jar.
So, if the function has this shape, we know that no matter how hard we try to get the numbers to move towards a certain spot (like the honey), they'll just keep wandering all over the place instead. That's why it's called the No Wandering Domain Theorem - it tells us that some functions will never lead us to a clear answer, because the numbers will just keep wandering all over the place.