How do I get dot Polkadot?

Excuse me, could you please explain how I can acquire dot Polkadot? I've been hearing a lot about its potential in the crypto sphere, but I'm not entirely sure where to start. Is it available on popular exchanges? Or do I need to mine it? Also, could you provide any insights into the best practices for storing and managing dot Polkadot securely? I'd appreciate any guidance you can offer.