Hi everyone.
I have a 10 year old Titan shed which is 9m x 6m in size. It gets awfully hot in QLD summers and I'm now deciding to insulate the walls and roof. I use my garage shed as a workshop for my 4x4 and also for home gym/man-cave area. So I am spending a lot of time in there. Currently it is just metal sheeting and I am asking the question regarding how to fix insulation to the metal walls and ceiling to prevent the insulation sheets coming off. String? Wire? are there particular fasteners available for this kind of retrofit? I'm looking at using either Foilboard 20 x 2400 x 1200mm Ultra 20 Insulation or Ametalin 1500mm x 20m ThermalLiner Roof and Wall Shed Insulation. I think the rigid boards might be the better option for me?

Any advice on fixing insulation to the walls and roof would be greatly appreciated.
Images attached of interior of my shed.