How does the confirmed quantity in distribution order get populated ?

In distribution order, In details line item, Users enter the order quantity against the item selected for distribution. Quantity can also get populated from the Sales order for which we are creating the distribution order. This is generally used in Job work transactions. If against a Sales order , line no of the Sales order needs to be selected. The Purchase Order field gets picked up from the Sales order in case of Job work transactions. Also a pop up is available to pick up Purchase orders manually. Once the line item quantity is entered the details get populated. Users can finish and confirm the transaction. On confirmation of the order, confirm quantity is populated which is equal to the order quantity of the line item along with the Confirm date, the date on which the document gets confirmed. Confirmed quantity can be issued and receipt in the shipped quantity.