I bought a used Cannondale Caad7 Optimo frame and fork. This is my first foray into the world of threadless headsets. The fork was detached from the frame for shipment, and when I opened the box, I noticed that various rings (parts of the headset) were slid onto the steerer tube, but there are no bearings. Also, there are not the traditional cups that I'm used to with threaded headsets. It is an FSA headset if that helps. I am assuming that the seller forgot to send the bearings with the headset. What kind of bearings are necessary or are bearings even necessary at all? How would I go about installing this headset? Thanks.