Metal shed/roof/ with window air conditioner/insulation foam board

I have an un insulated metal shed. Both walls and roof are metal. I bought insulation foam board for the ceiling that has the shiny foil on one side. I have a air conditioner mounted in the wall that I want to use. Which way should I glue the insulation foam board onto the ceiling? How do I reflect heat and eliminate condensation? I also have a exhaust fan mounted in the wall with a thermostat? I plan on running a commercial T-shirt heat press in the building from time to time. I need answers for the roof first of all and then answers for the walls? Thanks