How do you make 2 dropdown menus?

You can do two attributes. The first called “car maker” and the second “car model”. Then give the appropriate terms. More information here: https://docs.woocommerce.com/document/variable-product/

Worth noting though that this will result in hundreds of variations which isn’t great and would be good to avoid if possible. So unless you need a specific image for each combination and inventory tracked for each combination, then I would recommend doing something else like Product Add-Ons instead: https://www.woocommerce.com/products/product-add-ons/