Even though the chair is very good and comfortable, the cushions are clearly a design flaw. To be able to attach and adjust the back cushion, you need these holes in the backrest. Unlike the Epic, the Hero simply doesn't have them.

If they supplied the more expensive memory foam cushions, the problem would be solved.

Great chair, useless cushions

Actually quite easy ... why don't you follow the assembly instructions ?

You have to put the back part on the seat cushion so that the hinges lie on top of each other.

But first you have to mount the seat cushion on the gas pressure spring and the "feet+rollers" and pull the lever for the position of the back part CAREFULLY, the thing spikes back quickly. There should even be a sticker on it with a warning.