Hi Oscar! Sorry we didn't see your comment until just now. You should be able to open the game, click Settings (from the title screen menu), then Connection and change your Twitch username from there. You can't access this menu after you've already loaded a world, as that would cause problems. Once you've changed your Twitch username and started a new game, you should be prompted to connect to your Twitch channel. 🙂 Let us know again if you have any problems!