Appearance of Confirmed Quantity In Sales Order without having stock in Assembly Processing

Hello Experts,

We have ETO Scenario( Assembly Processing ) in where Auto Project created by Sales Order.

Whenever I'm creating Sales Order and Enter the Quantity >>> Confirmed Quantity is 0.

But, When Scheduling is carried out ( Network Assignment Performed ) >> confirmed Quantity is increased to Order Quantity without having Stock. How ?

Configuration Setting as below :

1. OVZ9

2. OVZG

3. CP

Material Master Data : Same Availability Control ( 01 ) is maintained in sales view. MRP type in PD.

Expert Pl. Advise.