2. Place the backrest (#3) onto the seat frame (#1). 1. Insert 4 threaded studs (#A) into the backrest (#3). Turn right to tighten. 3. From underneath the seat frame (#1) apply a flat washer (#C) onto the other end of the threaded studs (#A), then apply a hex nut (#D). Secure the nut using the wrench (#B). 2. Place the arms (#4) onto the sides of the seat frame (#1). 1. Insert 4 threaded studs (#A) into each arm (#4). Turn right to tighten. 3.