The wheel that shows up in that ad when I open it is NOT a 1956 Ford steering wheel. 1956 was the year Ford introduced the "deep dish" steering wheel to help reduce the instance of a driver getting impaled by his steering shaft - the "deep dish" was supposed to absorb and spread the impact.
A 1956 Ford wheel should look like this 1957 Thunderbird wheel.
If your wheel looks like this, here is how to remove it: 1) disconnect battery 2) with the palm of your hand, press down on the center of the horn ring over the Ford logo 3) while maintaining a downward pressure, twist the horn ring assembly counter-clockwise to remove it 4) now a standard 15/16" nut is exposed - loosen it and use a steering wheel puller to remove the wheel.
regards,
Jeff