There is a tutorial at https://docs.onflow.org/docs/non-fungible-tokens which describe the NFT interface.
AFAIK, the big difference in terms of interface is that FLow standard split transfer into deposit and withdraw but I don’t think it really matters. What’s important is how to maintain the mapping of contract address between Ethereum smart contract and Flow smartcontract as flow smart contract doesn’t have the notion of contract address (contract gets deployed into user account storage space). maybe flow smart contract should have additional meta field containing some sort of cross chain asset id
Curious to learn what Flow team has in mind.