The whole point of Laravel Forge is that you do not need to type anything in there.
Deploy Script is already there when you create new app on server.
Nginx configuration is also there so there is no need to do anything with it.
Maybe you wondering how to create new laravel app on forge? if that is the case then you need to create your local app first on your computer then you need to do your first commit to github and then you need to deploy that repositiry to your Laravel Forge.
Watch this tutorial it will explain in in detail: https://laracasts.com/series/learn-laravel-forge-2022-edition/