This can only used on line levels promotions.
This offer type can be used to give customer a value 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, this will be split between the applicable 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.