How do I perform a cryptocurrency exchange?

As a novice investor, I'm often overwhelmed by the complexity of cryptocurrency exchanges. Could you break down the process in a step-by-step manner? Firstly, how do I select a reliable exchange platform? What factors should I consider? Once I've chosen a platform, what documents are typically required for registration? And how do I ensure the safety of my transactions? Additionally, what are the common risks associated with cryptocurrency exchanges, and how can I mitigate them? Finally, how do I navigate the buying and selling process, ensuring that I get the best deals possible? I'd appreciate a clear and concise explanation to help me navigate this often confusing landscape.