Looking like a wall almost.
Thanks to a lot of preparation I had only to drill the holes in the wall, ceiling and floor which is very easy with a hammer drill even though the walls are rock hard. Now my language skills fails me since I don’t know the correct term for hammer drill. Anyways. It needs to be one with actual hammering (With SDS bits I believe). I have tried with drills with sort of a hammer function – completely withouth luck. It takes forever and you damage the drill bits.

Then I put in some plugs and screws and everything is actually sitting spot on where I wanted it to. The wood studs weren’t perfectly straight which you can’t expect but it will be fine when I mount the sides. I’ll need to shorten a few of them about 1 mm (1/32″) or something to get them in place though. And I need to think about where I want to install a ventilation hole in the wall…
I will have to wait for my new jigsaw until I go and pick up some sheets of MDF anyway. Also I need to remember to buy a decent respirator before I begin working on MDF. I thinks it’s formaldehyde or something nasty in that dust.