How to Upgrade NFT in Game?

Go to NFT->MY NFT.
Choose an NFT you want to upgrade. The price of the upgrade will vary depending on the level of the chosen token.
Press Upgrade. You will get a pop-up showing you a preview of the next level
Press Upgrade.
Approve Transactions in your MetaMask wallet. To proceed you will need a transaction fee in MATIC.
You will receive a ‘Success’ message from MetaMask and after a couple of moments, Your NFT will be upgraded to the next level. Previous level NFT will be burned.