How to buy Optimism on MetaMask?

Could you kindly explain the process of purchasing Optimism using MetaMask? I'm quite interested in investing in cryptocurrencies and would like to understand the steps involved in acquiring Optimism through MetaMask. Would it be possible to outline the necessary steps, including any prerequisites or special considerations that I should be aware of? Additionally, could you provide any insights or tips on ensuring a secure and smooth transaction process? Thank you in advance for your assistance.