can someone tell me how to wire one of these up?

Without seeing it, I assume that it's simply spliced into the main power cable.  Pressing on the switch completes the circuit, turning on the motor.  At least that's how I wired in my foot switch way back when I had a hand control.

Cut either positive or negative trolling motor cable. One wire from big foot to one end and other wire to other end. As previously mentioned, when you step on the pedal you now complete the circuit.