How do I buy and sell Ethereum on Coinbase?

I'm interested in understanding the process of buying and selling Ethereum on Coinbase. Could you provide a step-by-step explanation? I'm a beginner in cryptocurrency trading and would like to know what the initial setup involves, how to deposit funds into my account, and the exact process of placing buy and sell orders. Additionally, I'm curious about the security measures Coinbase takes to protect its users' funds and how long it typically takes for transactions to be processed. Your guidance in navigating this platform would be greatly appreciated.