When a manager sits down to "train" a new employee, the main focus is almost always on how to use the system.
But that approach leaves everybody frustrated. The employee doesn't actually know the context of when she should be doing those actions, NOR can she remember everything the manager showed her. And the manager is frustrated because he notices that the employee seems to constantly interrupt him with questions.
It's a lose-lose-lose (the system loses in this case, too) situation.
Instead of only focusing on showing employees how a system works, I recommend focusing on all 3 of these elements: