Hit the Mint an NFT button to mint manually and in the modal that opens you will be able to provide values for the properties you configured for the NFT collection.
Manually minting an NFT for a configured set of properties
2. View metadata
This example demonstrates how the fields in the interface are mapped to your minted NFT metadata.
Properties section while minting an NFT.
The values for those properties will be stored in the API's metadata collection and when calling the NFT contract for a certain tokenId and it will return an URL that points to the referenced metadata.