Comunication PC-arduino with apc220 module

Hi! i´m a beginner, recently i bought the APC220 module.

But i can´t make it work, i followed this steps:

1- Download drivers

2- Download the configuration module software

3- Connect the module to the USB adapter, which as you can see in the picture, brings to connect 7 pins (I've seen, others, only have 6 and left the pin module "Set" off, I to have 7 the I all connected).
The computer recognizes the device and installs and assigns port "COM 5"

4- Open RF-MagicV1.2A program, check Finding and give dipositive "Write" to upload the configuration to the module, this, I have done with the 2 modules, i don ´t know if it is correct.

5- Connect a module to the arduino mega2560 board

GND -------> GND
VCC -------> 5V
RXD -------> TX0
TXD -------> RX0

6- Upload the sketch with the USB this code

int val = 0;
int ledPin = 13;
void setup()
{
Serial.begin(9600);
pinMode( ledPin, OUTPUT );
}

void loop()
{
val = Serial.read();
if (-1 != val) {
if ('A' == val || 'a' == val) {
Serial.println("Hello from Arduino!");
}else if ('B' == val || 'b' == val) {
digitalWrite(ledPin, HIGH);
delay(500);
digitalWrite(ledPin, LOW);
}
}
}

7- Disconnect USB and insert module+USB adapter to PC

8- Connect arduino to an external power 7.5V to "Vin" and "GND"

9- Enter in monitor serial and send "bbb", but the led remains off.

I hope you can help me,THANKS!

i followed this steps:

but I'm not going to tell you what happened at each step.

I hope you can help me

I don't think so. Sorry.

Thanks