Cannot adapt Arduino code to ESP8266

Try this - see if the serial output is correct

/*
 * This ESP8266 NodeMCU code was developed by newbiely.com
 *
 * This ESP8266 NodeMCU code is made available for public use without any restriction
 *
 * For comprehensive instructions and wiring diagrams, please visit:
 * https://newbiely.com/tutorials/esp8266/esp8266-serial-monitor
 */

void setup() {
  Serial.begin(9600);  //why does NOBODY use a modern baud rate?
}

void loop() {
  Serial.println("ArduinoGetStarted.com");
  delay(1000);
}