Well, imagine you're a detective looking for clues in a giant library. Search engines use special programs called "crawlers" or "spiders" to scour the internet, reading web pages. They take note of key details, like words and where those words show up. Then, they stash this info in a massive index. When you ask a search engine a question, it digs through this index to find the most relevant answers. It's like having a super-fast librarian who knows exactly where every book is.