Hackers Help: How do I hack this Kallax headboard?

Recently I found a post with a light hack to use KALLAX bookshelf as child’s headboard. But I can’t find any tutorial, it seems to be very easy but in fact a bed width is 80-90 cm and if we put KALLAX bookshelf used in photo this way, its proof is only 39 cm.

Suppose it has been done with two units (39+39=78 cm) but it results small for a 90 cm bed, but I would like to adapt this idea to 90 cm measure. Any good idea or recommendation from expert hackers?? Please, need help, my child’s room is small and that’s a perfect idea.


~ Sue

Photo source: Unknown.

Jules Yap