Have not put this chair into use yet, but the mechanism on the bottom of the chair is manufactured backwards and the word "front" is actually the back on the bottom mechanism, so you have to remove that part (the mechanism under the chair seat) to be able to screw the back onto the chair bottom, then you must put the bottom mechanism back on. The instructions are clearly showing the mechanism is design to be used in the opposite direction than what the word "front" is indicating. For whatever reason, the word "front" embossed  right on the mechanism pointing in the wrong direction and the manufacturer put it on following that instruction, so it's backwards.

They provide the tools for you to do this and it's not particularly difficult.

I would buy the chair again in spite of this.