To create a product hierarchy in Odoo:

1. Go to Inventory → Configuration → Product Categories. Create top-level categories.

2. Add subcategories by selecting a parent category. Example: Electronics → Laptops.

3. Assign products to the appropriate category in Inventory → Products → Products.

4. Optional: Enable Variants for products with multiple options (size, color).

5. Once done, you can filter, group, or report by category in inventory or sales.

Tip: Plan your hierarchy before adding products to avoid duplicates and simplify reporting.