This can only used on line levels promotions.
This offer type can be used to give customer a percentage based discount, based on the number of products in the basket.
E.g. If you buy 10 of the applicable products you can get 10% off the lines.
Based on the breaks, you're also able to give customers a higher discount based on whether they have more of less of the products in the basket.
I.e qty break 1 could give a 10% discount if they have 10 of the applicable items in the basket, and Qty break 2 could give a 15 % discount if 15 were in the basket.
This discount will be applied to the basket lines before going to the checkout.