You need a button with the little spring coming out (white arrow points to it) of the side to contact the inside of your hub/adapter. The wire obviously hooks up to the male spade on the back of the button.
If you have to have to two prong Porsche button, then one of your wires coming from your button will need to ground to the steering column somehow.
A crude but effective way is to terminate a wire underneath the washer/nut that holds the steering wheel to the column.
That means just have a bunch of exposed wire sit under the big washer.