How do you set up the folder structure for a parallel route slot in your application?

You create a folder starting with an at sign, such as @analytics, inside the same directory as your layout, and Next.js automatically passes its rendered content into the layout as a prop with that same name, letting you place it wherever you want inside the layout's markup.

// app/dashboard/@analytics/page.js
export default function Analytics() {
  return <div>Analytics content here</div>;
}

// app/dashboard/@activity/page.js
export default function Activity() {
  return <div>Recent activity here</div>;
}