How do ENS domains work?

Could you please explain in detail how do ENS domains operate? I'm particularly interested in understanding the underlying technology and how it enables users to associate domain names with crypto wallet addresses. Also, I'd like to know how secure are these ENS domains and what are the potential benefits of using them? Additionally, are there any specific steps involved in setting up and managing an ENS domain? Finally, how does the ENS system ensure the uniqueness of domain names and prevent duplicates?