To apply a discount code to an order on TGW.com, customers should first ensure that they have their desired items in the shopping cart. Once they are ready to proceed to checkout, they will find a designated area on the checkout page to enter the discount code. It is typically labeled as "Promo Code" or something similar. Customers should carefully input the code in the provided field, ensuring that there are no typos or extra spaces. After entering the code, there is usually a button to apply the code. It is advisable to click that button to see if the discount has been successfully applied to the order total. If the code is valid, the new total will reflect the discount. If there are any issues with the code, it could be due to expiration dates, usage limits, or specific item exclusions. For more details, checking the relevant section on the current web page might provide additional information.