In FMS, the first four inputs are for planes and the next four for helicopters.
So if your channels are e.g. 4231, you will end with 42314231.
First concentrate on the plane settings (top four).
I suggest you take a model like the Bf109 to be sure of behaviour, and presence of all axes.
Your throttle is easy to recognize on the transmitter (does not come back to centre), and if briefly activated, will put a plane in motion on the field.
Then identify the direction (rudder), which will make you drive to left or right, with some throttle.
Next you will have to identify the elevator, which will put the plane in the air, if pulled with sufficent throttle.
When in the air, the ailerons will make you roll to the left and to the right.
As already said, for helis, just copy numbers in the same sequence.
FMS only uses the four tops for planes, and the four at the bottom for helis.
You could alse check your 'joystick' with Choose joy 1 or 2 in the menu bar, then press the 'joystick' button. It shows all axes and buttons, even the 'hat( view button.
Phil.