1. Find a coupon/deal you like
2. Click on the image/title or the "get deal/coupon" button and you'll get a
detailed preview plus the store page will open
3. If it is a coupon code/promo code just copy the code and paste it at
checkout before payment.
Usually in the input with the label: "Coupon code" / "Promo code" or "Discount code".
Show me some deals and coupons!