you plug the 2nd servo into the throttle channel of your reciever. you then should have the servo mounted to the msc. so heres how all of it should be:
-both servo's are connected to the reciever, in thier proper channels.
-the battery will conect to the msc, but dont connect it until everything else is set.
-there will be power wires that go to the reciever. plug it into the battery slot/"channel".
- make sure the resistors are properly hooked up, they're the white ceramic things.
- make sure you have the motor hooked up.
try it out. hook up the battery, and turn it on: it should work. if for some reason it does not, Imediatly take the battery out. a mislocated wire may cause damage to other electronics.
i hope that helps!