How to use a button normally close ?

Projects Programming
2 
const byte buttonPin = ; // the pin the switch is connected to
const bye LEDPin = ;     // the pin the LED is connected to.

void setup ()
{
  pinMode (buttonPin, INPUT);
  digitalWrite (buttonPin, HIGH);
  
  pinMode (LEDPin, OUTPUT);
}


void loop ()
{
  digitalWrite (LEDPin, digitalRead (buttonPin));
}

Connect your switch between your input pin and ground.
Don't forget a resistor for your LED (you didn't say how it is wired, I'm assuming between the output pin and ground)