I did not take it apart. I received it with the cog off and I am simply trying to put on the last few parts (cog, snap ring, driver cap, cassette joint, and lockring). I just want to make sure I am doing things correctly.

Here is a post and some pictures that may help.

I have a question about 2 of the parts that came with the Nexus hub. the parts in question can be seen in the link below.
i190.photobucket.com/albums/z180/Bolo_Grubb/nexus%20hub/CIMG0431.jpg


I think one of these might be the "driver cap" but I am not sure which one or if either of these is actually needed.

When I place the brass colored metal ring on the hub, it prevent me from getting the lock ring to lock in place on the cassette joint.

I can put on the smaller black ring and it seems to snap into place and I am able to get the lock on.

Please help me understand what these parts are and how I should use them.