The wires in the back of the apparatus (shown on the left) control damping and can be left off if damping is not required. It and is controlled by the large knob on the power supply.
A table showing different resonance values.
The 24 volt leads, connect to the top, and the voltage is varied by turning the knobs Fein (fine) and Grob (coarse) located on top.
The amount of damping is varied using the big knob on the power supply.