To create a promo code, go to the 'Promo Codes' section at the top of the page and click 'Create Promo Code.' Enter the title, description, and discount code (all codes will be in ALL CAPS). Choose whether the discount is a percentage or a fixed amount, set the quantity of codes available, and specify their validity period. You can also assign a promo code to a specific user on the WAX Platform. You can set up an unlimited amount of codes.