To clarify, I’m talking about information that you spent hours and hours on coming up with, researching, and world building, but these things aren’t directly related to the plot. This information isn’t required for the reader to understand the plot of the story, but helps make the world in which its set original.
Explaining this is a tricky situation, though. You don’t want to go too far and rove into Navel Gazing; where the characters sit and stare at the wall, contemplating how society is structured from top down and how they fit in that place. What normal human being honestly does that? Seriously, even introspective types don’t go that far.
Another option is to make use of an audience stand-in. Such as the Village Idiot. Gourry from Slayers is an example, and he’s used for comedy. He gets told things so the audience knows and then called an idiot since he really should have known this to begin with. But he is an idiot, so its ok.
Another common plot device is “From Another World” wherein the stand-in is from another world for real. They are legit confused about the landscape and what’s going on, which gives the author an excuse to explain. But this can easily be abused. Too much detail can kill your story.
That’s the boring way to get information to your readers.
The more fun way to do it is not to!
I get that you did spend hours and hours on world building, but having your characters simply exist in that world and not question the weird things that happen – to me, that’s fascinating. It’s like light switches. Someone from mediaeval times, reading a story set in our era would be mystified by the idea that someone walks into a room and the light comes on, filling the room with brilliance that was not from a candle? That isn’t something we would question because its so normal.
So let a lot of your weird stuff be unexplained. You know the reasons for it to be that way, and as long as its consistent in how it gets treated throughout the story, then your readers will pick up on it from context clues.
For me, I write aliens and their cultures and biology, by definition, are not Human. I can’t take 3 pages to have Vathion explain what Scent Bonding and Widow Syndrome are since he doesn’t have reason to explain that kind of thing to himself. I would need someone from outside the culture to ask questions about it. However, that’s still not a subject that would come up in casual conversation. The only way to get across the information that Widow Syndrome is a death sentence, fraught with dementia, is to just show it happening.
Writing a book is like constructing an iceberg. Only the tip – the story that ends up in the book – is visible, with all this other stuff lurking under the surface that supports it.