What you need to know
In the App Router, a page.js file inside a folder defines that route, while bracket folders define dynamic segments. A consistent route structure helps teams keep content, metadata, and loading states close together.
How to apply it
Use Link for internal navigation and a real href for destinations. Keep route slugs lowercase and stable, and check nested routes by opening their URL directly as well as navigating from the homepage.
Common mistake to avoid
Do not build internal navigation with plain buttons that change window.location unless a full document reload is intended. Keep a route map for important pages.