1. Log in to the Amazon website.

2. Click the navigation bar at the top and then click "Ranking".

3. In the ranking page, you can view the best-selling rankings according to different categories. For example, if you are looking for the best-selling electronic products, you can view the rankings under the "E-books" or "Smartphones" categories.

4. You can also view the best-selling rankings based on different sales data. For example, you can view the sales ranking each product has achieved in the past 90 days.

5. Click on the ranking page for a specific category and then click the "Details" tab. Here, you will be able to see all the products in that category and their sales data, inventory status and other information.