I borrowed one of these recently and it took a while to figure it out but once I did it was easy - and its as solid as a rock when assembled.
Open the flaps at either end of one of the racks. You then have to pull the inner bar of the flap (the one with the square/oblong tabs on) back towards the end of the rack then hook the little tabs behind one of the horizontal bars on the rack. I think its the next horizontal bar back from where the flap is joined to the rack.
Once thats done, and all three are assembled, just use the round tabs on each of the legs to hook into the round holes on the rack below.
Its all a matter of using spring tension to keep the thing together.
Hope this helps but as I've not go it in front of me I hope I've remembered correctly.
We've got one like that, and if it's the same it's simply a case of pulling it apart like a concertina and then the bars at the back run diagonally and fix into the holes. Now, don't ask me about taking the damn thing down cos that's another matter lol.
They get easier with wear!! Mine is about twelve years old and still sturdier than the new concertina ones, practise makes perfect so I would suggest a fair few camping trips!! (Any excuse)
I found mine difficult at first... but once you get used to it, it is fairly easy. I find holding the flat rack against my legs, with the legs pointing away and pull back towards me (hands on the legs, thumbs against the rack) to hook onto the rack. Also when assembling the 3 tiers together I have some sides that go in easily and some that are hard ... so if its the second set of legs on any tier that won't go in, then I start again with that side first, and then do the easy side. (I'm a weakling!!)
I'm not sure that I have explained it very well... but it actually goes together quite quickly now. (And recent discovery is to use a baby wipe to clean it down before packing it ... lifts any grease and food spills really easily).
Amazing family weekend with old steam engines, classic car displays, market stalls, and full catering and bar. And camping on site - Save £25 by booking in advance.