Swift Suntor 2004 bed assembly

Hi, I wonder if anyone knows if there is more than one way to put the bed together in my Suntor? I have managed to put it together several times but it's not very roomy, more like a big single. There are sections which slide out quite a bit more and I suspect (maybe wrongly) there are a couple of ways to put it all together. Hubby doesn't like the overhead bed or it would be easy! I just think I'm missing something obvious. Thanks in advance :)