Pages, layouts, and links

What this means

In the App Router, folders describe route segments. A page.tsx file creates a page, and a layout.tsx file wraps pages below it.

In beginner terms, this topic answers one practical question: "What should I write, and why does React care about it?" Do not try to memorize the syntax first. First understand the idea, then connect the syntax to that idea.

Why it matters

This makes navigation predictable. You can look at the app folder and understand the shape of the site.

When you build real React screens, this idea helps you decide where data should live, what the user should see, and what should happen after an interaction. That is why this lesson is part of the main path instead of being an optional detail.

Step by step

1. Notice the UI problem this topic solves. 2. Look at the smallest possible example. 3. Change one value and predict what should appear. 4. Run the example and compare the result with your prediction. 5. Use the practice task before moving on.

Small example

app/tracks/page.tsx
app/learn/[trackSlug]/page.tsx

Common mistake

Do not use normal <a> tags for internal navigation when a Next.js Link is available. Link gives client-side navigation behavior.

Practice task

Sketch routes for home, tracks, one track detail page, and one lesson page.

Remember this

Routes are UI organized by URL.