How to get your cat ID
Your cat ID is the NFT id & also part of the Cat Name.
If you don't know what cats you own go to https://opensea.io/account and check any pictures of gutter cats you see there
Double check that the ID is correct
You can always visit the official contract on etherscan https://etherscan.io/address/0xedb61f74b0d09b2558f1eeb79b247c1f363ae452#readContract
Under the Contract section -> Read Contract -> balanceOf function, check with your wallet if the query returns 1. If it return 1, the cat belongs to that address. If it returns 0, it does not