How do I buy swaps on Uniswap?

Hello there, I'm curious about how one goes about purchasing swaps on Uniswap. I've heard it's a popular decentralized exchange, but I'm not entirely sure how the process works. Could you provide me with a step-by-step guide on how to buy swaps on Uniswap? Specifically, I'd like to know what I need to do to get started, any prerequisites or considerations I should be aware of, and how the actual transaction takes place. Thank you in advance for your help!