Using a VBar you have free your mind from some knowledge concerning flybarred helicopters in the past. For example there is no direct connection between a stick movement and the servo throw and direction. The stick movement requests a target (turning) rate to the VBar only. VBar will move ther servos in the right way on its own until the heli reaches the given target rate according to the pilots stick command.
For the correct function and best result, it is required that the TX outputs all stick commands into the direction, with the center position and maximum values as we expect on our input from the RX. It is required to calibrate the TX to our expected signals. Therefore we use the servo direction, servo center (sub trim) and servo maximum in the TX for each of the 4 stick functions. The movement of the "real" servos inside our heli will not be set up here, this must be set in a later step in the VBar software seperately.
Select the TX calibration tab
You may find some examples in the documents linked below. Also check your failsafe settings according to the first document below.