Hackers Help: How to hack this Kura bunks with extra personal space?

Hi we have purchased 2 Kura beds for our boys who will be sharing a room in our new house. I drew plans to stack them and make a triple bunk bed with a spare bed at the bottom for when my nephew comes to stay… However more important than that, because we’re also looking at getting a sofa bed that he could sleep on, is for the boys to have their own space in the beds. I found this:

Which I think looks perfect, however… I’ve been looking at all the Kura parts and I can’t figure out how they go together as the dowel and screw holes all seem to go in the wrong place when trying to fit the bottom bed. Does anyone have any idea how you go about fitting the bed like the one in the picture? It definitely creates more use of the space than having the mattress above the side panels.