I just finished assembling the Vertex, but I have some parts remaining that I can’t place. Some are for the 2nd extruder and nozzle, but I have no idea what to do with the “Direct drive extruder filler” (2 pieces). This is the last part of this page:
The Direct Drive Extruder Filler part is an extra part if you would like to use the extruder body in a non Bowden setup. But for the Vertex you do not need this part.