I rarely rent cars but am going to Hawaii soon and will need one at HNL and then one at LIH. Can someone explain to me the coupon situation? What goes where for the following:

Discount Plan (CDP) Number:
Promotional Coupon (PC) Number:
Rate Code(RQ)
Convention (CV) Number

Also, I will be in HNL Saturday aft until Monday morning. I will then be in LIH Monday until Saturday evening. Any guidance for discounts would be appreciated.