Bought some secondhand roof bars for my 2012 Kia but tbh never fitted a set of bars before. I see they fit to the holes in the rail and there’s 2 keys to (I assume) tighten them on. Can’t find any instructions online to show me how to fit them properly, pretty capable practically but just want to make sure I’m doing it right… Any help appreciated, ta.

Sorrento owner. Got my bars from a mate who sold his Sportage, they clamp onto the roof rails. Has your car not got rails already fitted?
As for keys, do you mean spanner or hex/Allen key?
The bars I have are locked on when fitted. To fit I need to use the key to open/reveal a hole in the end of one side of the bars. Into this hole a 6mm allen/hex key is inserted to open/close the “jaws” of the clamping mechanism. Same on the other side but without needing to unlock the access port/hole.

Yes, the car has rails already. Mine are the proper kia ones, there’s 2 round plastic keys that go into cylinders already exposed on the sides so don t think they’re the same as you have ?