1. Initially, you have to identify the TeePublic discount code you're keen on from this page and click on Get Code, located on the right side of the title.
2. Next, you'll witness the offer code being showcased and auto-copied to your clipboard.
3. You'll then have to return to the checkout page of teepublic.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.