Suppose you're trying to teach someone calculus. Before they can learn calculus, they have to learn algebra. Before they can learn algebra, they have to learn arithmetic. This is the basic idea of inferential distance - background knowledge needed the understand the matter at hand.
Put this way, it looks simple, maybe not even worth talking about. But it's more subtle than that. To start with, arithmetic, algebra and calculus aren't single subjects. They're a whole bunch of related but still different subjects, which need to be learned independently. The learn integration, you have to learn differentiation, before that you have to learn limits, before that functions, variables, division, mulitplication, subtraction, addition... And don't forget the really fundamental things like what a number is.
And that's the really tricky part of inferential distance. There are a lot of things you know that you don't know you know. That is to say, you know them so well, it doesn't even occur to you to that someone else might not know it. Things that are so fundamental to your point of view that they're invisible to it. And so when you try to explain something to someone, you accidentally skip over a bunch of inferential steps, resulting in misunderstanding and each party will walk away thinking the other is stupid or crazy.
Consider a biologist talking to a creationist. They might try to explain the evidence for evolution, but before the creationist can understand that, they have to understand what evidence means, how science works, maybe even something as simple as why truth is important...