I know NFT are non fungible (virtual) like digital paintings. But what makes me confused is that, for example, MurAll (PAINT) at $0.00399200, how is it sold? NFT owners owners a token to prove the authenticity of the art work, in this regard, will you be the only one that will buy MurAll (PAINT), or others will buy it and use it to trade?

Let me make it more understandable. Assuming I bought $6 million worth of NFT and I have the token with me which proves me to be the right owner, can I list it on exchanges so that people can trade it like bitcoin and other crypto assets like ethereum and litecoin?