I can't see metadata displayed on OpenSea

This is the contract: https://rinkeby.etherscan.io/address/0xa4Aa6d7b4E02eeDBa41ef0A3e56EcabAe7bdc719#writeContract
This is the OpenSea page where I want to display my NFT: https://testnets.opensea.io/assets/0xa4aa6d7b4e02eedba41ef0a3e56ecabae7bdc719/1
I uploaded my metadata using ipfs using Pinata but OpenSea cannot fetch it. What's going on?
If you need more informations on this pelase tell me so that I can help you.

You need to implement the function that return the Metadata about you collection. Otherwise you can log in to opensea with the same wallet as the owner of the contract and edit the details. You have to import the collection.