Question about vapor/moisture barrier

[AbnerFurmond]

Hey all, I have a steel garage and was considering sectioning off a small section into a pool room that is temperature controlled.
It is a steel garage with steel beams every six feet for the supports which the siding is connected too.
If I make a stick built wall there will be a 4 inch gap in between the siding and the studs of the stick wall.
Is it necessary to put a vapor barrier in between the wall and the siding since there will be a lot of draft in between there?
I am in the deep south btw, Savannah GA to be exact. If that matters.
And if I do put a VB in there, would I put it between the steel siding and the wall, or in between the wall and the drywall?

 

[AbnerFurmond]

Any guesses?

 

[camarotoolman]

I would put it onthe outside of the studs. Do you ever go to Kellers flee market,I used to sell tools there?

 

[AbnerFurmond]

Unfortunately not enough. I work long hours.
Can you explain why I would want to do this. Not that I doubt you at all, I am just very confused about vapor barriers and how to use them. It seems like half the people say always in between the studs and drywall, and the other half is always the opposite.