I have a Daihatsu Fourtrak 1993 2.8 TDX. Someone has offered me a roof rack but I can't work out how to fit it. The roof of the vehicle is on two levels and there are metal studs on the high part which seems the obvious place for the rack to fit to. The rack has bolt holes on four corners. I tried hooking one of the studs out but it didn't move so I gave up, not being sure that that is what I should be doing.

Is there anyone with more experience of these things that can can give me some advice.

Thanks