How to add fields to a node

    Hello. How do I add fields to a commerce node? For example, when a user visits the product page, there is a price, a title, and the variations that exist in the relationships. I tried to set up relationships for the product, but nothing works. There isn't an option, for instance, to specify the quantity of products when already placing an order.

 How can I display the "quantity" on the product catalog page?