1. Replicate the promo code for Showtime you wish to use from the page, and click to get code.
2. You will subsequently see the offer code appear and get automatically copied to your clipboard.
3. You'll then have to return to the checkout page of showtime.com, find the designated box for the promo code, and enter the discount code you had previously copied.
4. Ultimately, by clicking 'Apply Code', you will be able to see the discount amount on your existing order.