Can I buy Polkadot on MetaMask?

Hello, I'm curious about something. I've been hearing a lot about Polkadot recently and I'm interested in investing in it. However, I'm a bit confused about how to proceed. Could you possibly clarify for me if it's possible to purchase Polkadot through MetaMask? If so, could you provide a brief outline of the steps involved? Also, are there any specific risks or considerations I should be aware of before making such a purchase? I'd really appreciate your help in navigating this.