Step 1: Choose the NFTs tab and click the "+" button on the upper right corner of your screen.
Step 2: Enter the NFT details. You would need to specify the network you have the NFT on and the specific contract address. Then click "Import".
SubWallet would automatically perform an on-chain search to fill in other details such as NFT type and NFT collection name. In some cases, you would be able to name your collection.
Step 3: Would would be re-directed back to NFT homescreen. Your newly imported NFT (in this case, nepa) should be visible there.
Please note that one of the accounts you are managing with SubWallet must be the owner of the NFT. If you import an NFT you do not own (even though you know the network and the contract address), or if you are not managing the NFT owner account with SubWallet, the NFT would not appear in SubWallet.