I recently ordered a new wheel set for my ~1988 7-speed mtb bike (I mostly ride my Trek 5200 road bike but the mtb is great for camping and riding around the neighborhood with my kids). Anyway, I ordered a wheel set with a 7-speed free hub and they sent me a free upgraded hub with a 8/9-speed free hub along with a spacer. I don't want to change the rear derailer and shifter as i am happy with the setup (Specialized Rock Hopper Comp w/ Shimano Deore LX indexed single thumb levers).

So my two questios are: 1) do i place the spacer on the free hub prior to the cassette or between the outer small gear and lock ring? 2) The cassette came with a small gear (13), lock ring and a small washer with circular inward notches. The notches align with the splines on the free hub but i don't know where to place it (e.g between cassette body & small gear; before cassette body; etc). Where does this washer go?

Thanks