67 standard steering wheel-horn contact help?

I've got a standard contact ring kit from scott drake but am not sure how it all goes in. The PO of my car removed all of the bits from the inside of the horn ring except for the attaching ring that holds the horn ring on. Please note I've previously replaced both horns, all wiring, volt. reg, alt, batt and the contacts that mount to the column - this is the last bit to (hopefully) get it working.

From referencing the column - I can tell which way the contact plate goes. then three pins on one side of the spacer line up with the attaching plate and the three pegs on the opposite side of the spacer line up with holes in the contact ring -

but

what's the donut for?

and

does something come out of the center of the pad to hold the contact ring and spacer against the attaching ring? If not it just floats in there and won't make contact.

I tried the donut as a spacer (didn't really fit so I didn't think it was right) between the wheel ring and the contact plate - but it shorted when I engaged the horn. Which tells me the circuit is passing gas - but not in the right way I guess.

Any thoughts? I'm missing something here most certainly and I don't understand the theory of the circuit so I'm baffled as to which parts I've got wrong - thanks