The two things on the stem are the dust seal and the locking ring, take these off and slide the stem into the frame, the bearing at the bottom will sit in its race. Put the top bearing in (not shown) it will also sit in its race flush with the frame. Put the dust seal on (lip down) and wind the locking ring on to tighten the whole thing up, make sure it all moves smoothly. You want to tighten that ring until the steering starts to stiffen up and then back it off a little. Put the top triple clamp on and then the big nut (not shown) on top of that, dont forget the top pinch bolts.