Insulation, Radiant and Vapor Barriers - insulating metal garage

Last summer I purchased a home with a 30'x40' metal sided and roof building. I had concrete poured over the dirt floor and want to use the building to restore my antique pick-up and put in a woodworing shop. The problem is in the summer it's an inferno and in the winter it's colder inside then out. Also I've noticed the interior metal wall sweat in the winter and form a thin coating of frost on them. Can I insulate the wall and how do I proceed. Do I need a vapor barrier? Will 2x4 studs be sufficient, currently the beams that hold the building together are 4x6 on 10' ctrs. There is no ceiling and the peak of the roof is 13' with 4 skylights. Can some please advise me on hoew to remedy this condition. Thank you ...... Serge

Metal siding and a metal roof? I would use 2X6 studs and R-19 insulation. Put a ceiling in it, and R-38 insulation. Make sure the attic is properly ventilated. Install lite shafts under the skylites, with R-38 insulation on the walls of the shafts.