This guide will tell you how to play CO-OP in Pokemon Scarlet and Violet | Yuzu Emulator.
You will need to boot up the Yuzu emulator and click on the Emulation button from the top. After that, select Configure from the drop-down menu and then select System from the left side. Go to the Network and set the network option that you are currently using on your system.
At the bottom right of your screen, you will find an option popping up which is saying not connected. You have to double-click on it and then a window will pop up in front of you. Input your nickname and select the game you own as it will show you the list of the games that are currently loaded in your Yuzu emulator. You have to sort the list by players and then click on the Refresh List button.
After that, you need to join any pokemon game with more players. For this, you have to double-click on it and then a new window will pop up in front of you. It will be a chat box, and you will find all the people who are connected. At the bottom right side, you will find that now it says connected.
Now you have to launch the game, then go close to the screen in the game and click on Join game. It will take you to the enter code page, and you need to paste the code of the game you want to join. Once you have joined the game, you can play co-op.