Coupon codes on imported orders differ from coupon codes on manually entered orders in that they are applied on the item level versus the order level. Coupon codes on imported orders also do not apply a discount automatically therefore the discount fields in the import must be populated with the value of the discount for each corresponding item on the order. To enable coupon codes you would setup the coupon code under Company Data -> Advertising -> Coupon Codes. The following is link to a training module regarding how to set up coupon codes:
Adding & Editing Coupon Codes Then navigate to Company Data -> Advertising -> Maintain Scripts and check "Allow Coupon Codes" on the Demographics tab (Coupon Code Source in that case should be OLX) of each applicable script.