/app: Contains all the routes, components, and logic for your application, this is where you'll be mostly working from.
/app/lib: Contains functions used in your application, such as reusable utility functions and data fetching functions.
/app/ui: Contains all the UI components for your application, such as cards, tables, and forms. To save time, we've pre-styled these components for you.
/public: Contains all the static assets for your application, such as images.
/scripts: Contains a seeding script that you'll use to populate your database in a later chapter.
Config Files: You'll also notice config files such as next.config.js at the root of your application. Most of these files are created and pre-configured when you start a new project using create-next-app. You will not need to modify them in this course.
Reference: https://nextjs.org/learn/dashboard-app/getting-started
Folder structure