Get serial port data on matek 405 wing v2 [solved]

Hello everyone, I have problem - get or resive any data by Lua script by serial port from Matek 405 wing V2.

Hardware part : for resiver I use arduino nano. For transmission I use matek 405 wing , with ardupilot v4.5.7
FC connect to arduino nano by GDN to GDN, TX4 → D2, RX4 ->D3 on arduino and use Software Serial port by UART D2 as RX,D3 as TX port.

Software part: In Ardupilot for Serial4 protocol 28. For send I use Lua script with simple code from example - “serial_test” :

local port = serial:find_serial(0)
port:begin(9600)
port:set_flow_control(0)

function update ()
  if port:available() > 0 then
    read = port:read()
    gcs:send_text(0, read .. " = " .. step)
  end
  if step > 122 then
    step = 65
  else
    step = step + 1
  end
  gcs:send_text(0, tostring(step))
  local m = port:write(step)
  gcs:send_text(0, tostring(m))
  return update, 1000
end

return update()

On message I see then m = port:write(step) always return 1 , but I don't see any information on my arduino.
For arduino I use next code :

#include <SoftwareSerial.h>

SoftwareSerial mySerial(2, 3); // RX, TX

void setup() {
  Serial.begin(9600);
  mySerial.begin(9600);
}

void loop() {
  if (mySerial.available()) {
     Serial.println(mySerial.read()); 
  }  
  delay(1000);
}

I try connect FC to UART serial port : GDN to GND, TX4 to RX, RX4 to TX on UART serial port - and I don’t see any information on serial monitor.

Can please help me , don’t understand what I do incorrect? Thank you.

Sorry It is was my mistake. I not understood what’s mean F4 based autopilots in lua script documentation. I changed matek 405 wing to matek 743 wing and all code now work well. Thanks to all . Topic can be closed.