steering wheel install

My boy just replaced the key lock on our '79.  We started putting everythig back together as he had it layed out for easy installation.  The problem is after you put the blinker assembly in you install a thrust washer a spring then the contact assembly for the horn followed by a large "spoked" keeper then you have to put a "u"clip on to hold evrything which requires all the parts to be compressed.  Is there a trick to compressing this or are we putting it together wrong.  My assembly manual does't show this.  Also there is a plastic piece that goes on after the u clip.  Mine was broken do you know what this piece is called.