Crew Management Questions

As far as Crew Management how does it work exactly?? Like qaulified people (torpedoe men) raise the efficiency of the area theyre qaul'd in ?? and Officers raise it no matter what? especially if theyre qaulified??

What about the green bar above each compartment, say I have the conning tower with 2 men on but full green bar, (a watch officer and a qaul'd watch petty officer) do putting more men increase the efficiency even more??

And do medals and badges do anything besides looking nice assigned to anybody?

Just wondering guys thanks?