I got an Ikea Oppdal bedframe for free, put it together, and seriously was waiting for some nightmare like this.

Everything was great. I think I was missing one screw. One screw. Amazing.

So, I'll give you some advice based on my experience lurking here and learning about Pozidriv screws.

1. Go online and look at the various Malm bed frames. Looks like you need to figure out if you have a queen or a full size frame. I looked a little. A Full size Malm, the width of the Headboard and footboard is 150 cm (59"). Queen size is 168 cm (66-1/8 in.) Once you figure out what size you've got, go the product page and get the assembly instructions and go through it carefully. Don't skip anything. Your second picture shows a mangled cross brace. Go to Ikea and replace that part. Take the old one, they might just replace it even though it looks like it was run over by a truck.

2. On to the slats.

Eldfoss?? Google said "What is that???" and I agree. What is that?

These are Lonset slats it appears. Get the manual for the Lonset slats and do the same thing, make sure they are put together correctly. They look messed up.

It is possible you've got a Malm bed frame and some copy cat slats for another bed, which are close by not quite there. Depending on where you are and your transportation options, you can often pick up a Malm frame for cheap or free. Try Criagslist.

Good luck.