You will see either a Calculate or Apply Deal button based on which Ordering mode you are in:
Calculate
This button appears in Products Ordering mode.
When pressed, it analyses the products with an order quantity against the potential benefits they can receive from triggered deals, then automatically applies the best one possible.
Apply Deal
This button appears in Deals Ordering mode.
Assuming you have already selected the deal you intent to use, pressing the Apply Deal button will force any products in that deal to use it if it meets the minimum order quantity necessary to obtain the benefit.
A product can only be linked to one deal per order - so if the product is already assigned to a deal and you switch to another one that also includes the same product, pressing Apply Deal will prompt a message advising you that if you want the new deal then it will be removed from its current one.
