How does a collectibles redemption interface work?

I want to create a simple interface for the following steps:

1. User connects metamask wallet
2. Platform detects NFT within the wallet
3. Platform checks if wallet / NFT is in the whitelist
4. If true, a file (e.g. an image) is downloaded

I’ve reached the end of the internet and I couldn’t find any tutorial / repo that has this. Inexperienced programmer here, any help will be highly appreciated