I bought a wooden board 80cm x 20cm. I draw the measures like this;
I cut the pieces with hand saw and sand papered the edges;
Place one leg against the wall and screw the hinge in. Do the same with the other leg;
Place the sitting board onto the floor and against the wall, then place on of the legs onto the board and screw the hinge to the board. Do the same with the other leg;
And that is pretty much it :) you have a handy Seiza Bench in just a few minutes and for very little money;
The bench can be folded which makes it easy to bring along on holidays or similar;