//include this library for servos
#include <Servo.h>

//next call a specific class by initialize servo, create a servo object
Servo myServo;

//function declaration
void setup() {
  myServo.attach(9); //attach to pin 9, could connect an LED as well and it will do something.
}

//now a loop - will run forever as long as the arduino is powered.
void loop()
{
  // go to postion 0, can write a loop to have it keep moving to several positions.
  myServo.write(0); //call write method and go to home position, 0
  
  delay(500); //go to home position and wait, because it takes time to get home
  myServo.write(180); //a second write, half turn from home - 180 (maximum commonly for standard servos)
  delay(500);
}