What is ERC-721? ERC-721 is an open standard that describes how to build Non-Fungible tokens on EVM (Ethereum Virtual Machine) compatible blockchains; it is a standard interface for Non-Fungible tokens; it has a set of rules which make it easy to work with NFTs. Before moving ahead have a look at all the functions supported by ERC721.
You want to give your early supporters access to a whitelist for your collection, so here you are creating an whitelist dapp. More info on LearnWeb3.