In order to sell your NFT you need a connected external wallet which will be used to collect the funds once your NFT is sold. Click on the menu to connect your wallet.  In the menu you can also find the ‘My collection’ section with all your owned NFTs. Go to your NFT collection and click on the NFT you like to sell.  Don’t worry if your NFT is bought with the DaVinci wallet. When you click on ‘Sell’ you will be asked to confirm a transfer of the NFT to your connected external wallet. Small note: you can only resell NFTs bought on DaVinci.