Okay, let's start building the foundation for an advanced agriculture web application.

First, ensure you have react-router-dom installed: npm install react-router-dom or yarn add react-router-dom

Here are the initial files for the project structure:

This sets up a basic application structure with a header, sidebar navigation, and placeholder pages for Dashboard, Crops, Fields, and Weather using React Router. We can build upon this foundation by adding specific features, components, and data handling.