How to make API calls through their library: https://docs.tmijs.org/v1.2.1/Twitch-API.html
The API endpoint you’ll need to use to update game: https://dev.twitch.tv/docs/v5/reference/channels/#update-channel
The docs for how to listen to Chat events: https://docs.tmijs.org/v1.2.1/Events.html#chat
Where it says // Do your stuff. in their example, that’s where you’ll put your code for your commands, such as !game, if you want to be able to use something like ‘pubg’ instead of the games full name, then you’ll have to have to make a list yourself of the games full names (as that’s what the API requires), and the games shorthand that you want to use in your command.