The black piece on the left goes behind the plastic bit which is for the wiring loom in the yolk assembly (which are the black and white wires)
The middle bit is for the brush upright switch on the left side of the vac inside, it should have a spring for the micro switch
The one on the right goes inside the innse left hand side of the yolk assembly and it's teeth correspond with the holes of where the yolk sits :)