How do I buy and sell ETH?

Hello there, I'm curious about the process of buying and selling Ethereum (ETH). Could you please explain the steps involved in doing so? I'm interested in understanding the different options available to me and the factors I should consider before making a purchase or sale. Additionally, I'd like to know about the security measures I should take to protect my investment and the potential risks associated with trading ETH. Thanks in advance for your guidance.