I purchased a Box of tide laundry Powder detergen...

I purchased a Box of tide laundry Powder detergent detergent. I normally purchase liquid. Marketing coupon on the Box claimed 8 dollar coupon when you purchase this product. I assumed the coupon was in the Box. But no coupon and no explanation of where to print out your my coupon. How do I redeem the coupon I purchased the product I would like the coupons?