How do I offer discount to whole order?
  1. To make an order, Kindly use the steps 1 to 6 from the link 
Making an order  2. In the 
Order screen select ... option available next to the 
Order type. Select 
Discount from the drop down list 
  3. A pop up named 
Discount gets splashed. Discount on 
Order list can be offered by using the 
Preset and 
Manual options
Preset, displays the predefined offers available. Refer > link to create a new discount offerManual, allows to offer discount using Percentage value or amount. The Reason for offering discount can be specified in the Enter reason text box  4. To complete the transaction follow step 6 & 7 from 
Making an order