Manufacturing process

Hi all
Could you help me with manufacturing logic?
The situation is that: I need to create a manufacturing order with 2 operations: manual assembly carried out by the Technik and the quality check carried out by the Engineer.
My questions are:

  1. How does each of them start and finish their operation? How is it implemented?
  2. How do I prevent a technician from completing a production order without passing a quality check?