This is mainly a user community forum. We can't see your particular discount, but many partner discounts are "Up to $20", which means it depends on the product edition, such as $20 for Self-Employed, $15 for Premier, $10 for Deluxe, etc.
Does your coupon show a special website to use? That's how it normally knows to apply any discount. Or are there any instructions on your coupon? Rarely there is a coupon with a discount code instead of a website.
To have the discount applied, you usually have to start your return by going to the bank's website and finding the TurboTax link. You have to go to the special discount website to start TurboTax and go there each time to finish and file the return.
FAQ: How do I get my TurboTax affiliate partner discount?