So I am planning to write a story using third-person limited perspective where the only elements seen are those known to the main character. The nature of this world they inhabit is extremely alien and unique to our own experiences however, and highly relevant to the plot, but for the inhabitants who have grown up in this world, it is a normal part of their existence and rarely worth comment.
I don't really want to use some worldly outsider as an excuse to exposition dump, but I feel it's important to establish very early some of the basics about how this world's structure is unique.
Any tips on how I properly convey the exposition to the reader without making it seem uncharacteristic to explain it within a third-person limited frame? I thought about maybe using an omniscient voice at first to detail the basics of the world in the first few paragraphs, but was unsure if the shift in tone from omniscient to limited shortly after would confuse readers. I also considered an introductory chapter similar to Lord of the Rings where Tolkien deep-dives into the culture of hobbits, but I am a bit reluctant to have a "science of the world" chapter shoved in before any hint of the story even begins since I know the beginning is important for hooking the reader, and would rather not delay that by a whole chapter.