Yep that's the one, on mine I have the receiver connected to it, the unit goes in between the receiver and the servos BUT
you can just run the unit with power and the appropriate servos and have everything else as per normal, the Sig from Tx (Aux channel) is to enable switching the stabilization on or off from the TX, not needed for our purposes.
My exact set up is Rx rudder and ailerons connected to Stabilizer rudder and aileron, Stabilizer rudder to ships rudder, aileron to Y lead and one servo in each Y lead, so one servo drives one fin, as the servos are mirrored operating one direction has the opposite effect on each side. I needed to make up some female to female servo leads for the interconnects between the Rx and Stab module. Can be purchased as well.
The only reason to connect the ailerons to the Rx is to heel the ship to impress the crowd

the rudder does help to keep it in a straight line, I can sail from one side of our 300 M lake to the other with barely a deviation, All because I can not because I need to If you get what I mean