Hi, you need to set the shopping cart price rule now.
Navigate to Promotions>shopping cart price rules>add new rule
in the Rule Information tab you set your discount presentage or fixed amount, chose the group this discount is applied andfill out other fields you’s see.
in the Conditions you set:
If an item is FOUND in the cart with ALL of these conditions true:
* Quantity in cart equals or greater than “ put your qantity here”
You can also set here also amout of order.
Besides you will see that you can set other conditions.
Fill out tab “Ations” also set there “Apply the rule only to cart items matching the following conditions” with the same options set up in “Conditions”