I'm relying on my memory here. My KYB's are still solid after 120K miles or so, so I haven't done this in a while.
Typically, you install the lower washer, then the lower bushing on the shaft, install the shaft in the mount, install the upper bushing, then the upper washer. Then you install the nut and torque as indicated.
The top and bottom washers *may* be different. Possibly only one will slide on the shaft far enough to allow the bushings and nut to be applied. The other one may not go on very far at all. And the bushing *may* be directional; that is, one end of each may face the washer and the other may face the mount.
N