The coupon for the25 GB of bonus data does not require you to perform any action to redeem the coupon. The bonus data will be automatically be added to your mobile number.
The coupon for service credit will be automatically added to your credit balance. Thereafter, your service credit can be used as specified in Question 8.
It is a simple process since you will not have to manage any special coupon codes nor will you have to perform any special task to redeem your coupon.