How to attach a hook for ceiling lamp

[Trekul]

I have a problem. I bought a new ceiling lamp that weighs 4 kg to put up in the living room. There is no hook, so I need to install a new one. I believe the ceiling is made of treetex (I'll provide a picture later). I read in another thread that there should be sparse framing behind the longitudinal joints. Will this support a ceiling lamp, and is a regular screw hook sufficient, or do I need a stronger fixture?

 

[Testarn]

If you hit a regel/glesen, a screw hook with wood thread will suffice. 4Kg is not that much.

 

[Trekul]

Now I have drilled a hole in the gap between the panels, but did not manage to hit wood. Attaching an image. Also trying to tap to hear if it sounds solid somewhere. What kind of construction could it be, or how should I find something to attach to?

 

[Trekul]

Should I go up to the attic and try to dig through the sawdust to find out how it is set up and where there is wood to attach to? Or is it better to drill more holes on the off chance?

 

[jonaserik]

You push up a wire 30 cm or similar into the drill hole, when you reach up, you find it. Otherwise, you have to be a grävling to find it. You become disoriented up there.