Discount coupons can be generated for guests as an incentive for them to make bookings.The 'valid from and to' are the dates the booking can be made on and not the booking itself. A useful tool to generate business.
When you create a new coupon, the booking system will automatically create a unique code for you, however you can change this code to something else if you like.
The Valid from/to dates refer to those dates when the coupon can be used.
The Booking valid from/to dates refer to the dates the booking must be for. If dates of the booking fall outside of those periods, the disount isn't applied to those days outside the booking valid/from period.
The Guest Name option allows you to make the booking usable by just one guest, if you leave the dropdown empty then any guest who knows the coupon code will be able to use the coupon code.