The head comes sealed in a plactis bag already assembled as shown in the photo below. All you have to do is build the flybar cage (don't forget to pop on the link) and assemble it onto the head with flybar attached. Then comes the painful part: threading on those tiny ball links. Just clamp the link rod with a plier, and then thread them on with your hand. Do not crimp the plastic links with plier during assembly, as it could cause damages to the link. The head assembly took no more than 15 minutes, with most time spent on those links.