I went through the assembly instructions and cut this out. Give this a try.
Wire up the spindle power supply as shown. You may connect the power supply to the controller in order to use software controlled ON/OFF, or you may connect the supplied knob for optional speed control. Connect one or the other, but not both. Connecting both will not harm the hardware, but it will not have the desired effect either, requiring both knob and software to activate the spindle, however not utilizing any speed control.
Note that your supply may have a switch for 110V or 220V, ensure that it is set to the voltage you intend to use. If a switch is not present, then it must be supplied with 220V AC power.