To use this module, you need to:

#. Create a new sale order and choose a partner.
#. If the partner has customer global discounts set, those will be applied to
   the order by default.
#. Otherwise, you can set them manually from the header of the sale order.
#. In the order footer, you can see the computed discounts.
#. When you create an invoice from the order, the proper global discounts will
   be applied on it.