NFT stands for Non Fungible Token. 
It basically means an unique token which is wrote into some of the crypto blockchain.
One bitcoin is fungible, you can change one for another similar.
For example limited edition collecting card is non fungible you cannot change it to another similar one.
(NFTs can be multiple similar pictures etc., but the block chain code behind each of them are different)

Money Zebra NFTs are tied to Polygon/Ethereum chain.
Polygon is a 2nd layer for Ethereum. It makes the transactions much faster and cheaper.
For example, Disney, just announced that they will use also Polygon for their future NFTs.

Since NFTs are tied to some block chain, you need to have a crypto wallet.
With crypto wallet you will get an address for the crypto.

Each coin or token should only be sent to matching chain address. 
In Money Zebra NFT case to Polygon address.

Polygon address example : 0xC640b4fFf7A02e75b03c66f369A8f0aAdb5d170a

The one of the most user friendly wallet is Metamask wallet.
Metamask can be downloaded from Google Play store or as Chrome web browser extension.

In order to receive Polygon address, you must connect you Metamask wallet to Polygon-Network.
Good instructions can be found for these from:
https://www.coindesk.com/learn/how-to-connect-metamask-to-the-polygon-network/

You can sell and buy NFTs at Opensea.io. 
In order to do so, you need to connect your Metamask wallet to the account.
https://support.opensea.io/hc/en-us/articles/360061676254-How-do-I-create-an-OpenSea-account-
https://opensea.io/collection/money-zebra

Once you have the Polygon address, just follow this instruction:
https://moneyzebra.eu/whitelist