Use this option when you already have coupon codes generated (e.g. by your e-shop) and you want to import them to Post Affiliate Pro (PAP). You should paste them into the text area labeled as "Coupons" and separate them by comma. All these coupons will be then used in the system.
There are two options how affiliates can use it.
Affiliate will get coupon upon request - coupon codes will be free and affiliate will be able to ask for allowed number of coupons (based on Maximum coupons per affiliate). If there are any unassigned coupons, affiliate can use "Get another coupon" button. It will assign a new coupon to him.
If you choose this option, you as a merchant will be able to manually assign particular coupon to an affiliate.
Assign automatically - coupon codes (defined number) will be automatically assigned to the affiliates (based on Maximum coupons per affiliate) so they will not be able to ask for more. If you create much more codes than number of affiliates, then they will be able to have assigned another coupons.
In both cases, if there are not enough coupons for all the affiliates, only first affiliates will be able to get coupon codes. E.g. if you can only offer discount in total amount of $1000 and each coupon is for $10 and you have 110 affiliates, then ten of them will not get a coupon code if you give one coupon to each affiliate.