If you want the torque to move you forward then you should use the “right vector” as the input axis – like a wheel axle. Forward/backward will be positive/negative values or vice versa – not sure which.
So the torque vector should just be GetRightVector() from the camera (tho if you’re doing the camera right then I’d use GetControlRotation() and get a forward vector from that). Then multiply that vector by the axis value and apply the torque.
And for right movement, use the forward vector (again, left/right will depend on the sign, not sure which but i bet right is negative).
I think that’s what you’re asking and what the docs say.