Private asset & NFT

Hello. I am investigating to have informations about the relationship between NFT and a native asset. I mean that I would create a private Asset and its own NFTs. The NFTs are a set of elements in the asset itself. They should not exit and they should not fly away. Could you please suggest me the documentation about the working NFTs and user own asset? Thanks.

You might want to start from the native token developer portal and then keep asking in the forum.