How does Changelly work?

Could you please explain in detail how Changelly operates? I'm particularly interested in understanding the process from the moment a user initiates a transaction to the point where they receive their desired cryptocurrency. Does Changelly facilitate direct peer-to-peer exchanges, or do they act as an intermediary? How does the platform ensure the safety and security of user funds during the exchange process? Additionally, what are the fees associated with using Changelly, and how are they calculated? I'm eager to gain a comprehensive understanding of how this popular cryptocurrency exchange platform functions.