Reading data received from Nextion on Serial Monitor

Other Hardware Displays
3

While I am sure my Nextion and Arduino codes are wrong ,I am looking for some way to display
the data received on the Arduino so I can see where I am going wrong. Similar to the Arduino Serial.print command which displays to the Serial monitor.
Attached are HMI and Arduino codes.

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tvoid setup() 
{
  Serial.begin(9600);
  pinMode(8, OUTPUT);
  digitalWrite(8,HIGH);
  delay (2000);
  digitalWrite(8,LOW);
}

void loop()
{
  String Data_From_Display = "";
   if(Serial.available())
 {
 String Data_From_Display = "";
  delay(100);
  while(Serial.available())
  {
    Data_From_Display += char(Serial.read());
  }
    if( Data_From_Display == "ON")
     { digitalWrite(8,HIGH);}
    else if( Data_From_Display == "OFF")
     { digitalWrite(8,LOW); }
    else
    { 
       
       Serial.print("page0.t0.txt=" + String('"') + Data_From_Display + String('"'));       
       Serial.write(0xff);
       Serial.write(0xff);
       Serial.write(0xff);
    }
 }
 delay(2000);
}ype or paste code here

What I am after is some way I can Serial.print to the Serial Monitor to show me what I have
received from the Nextion.