#define led 0  // pin 6 physically, top left in this case
#define button 1  // pin 5 physically, bottom left in this case

void setup() {
    pinMode(led, OUTPUT);
    pinMode(button, INPUT_PULLUP); 
}

void loop() {
    if (digitalRead(button) == LOW) { 
        digitalWrite(led, HIGH); 
    } else {
        digitalWrite(led, LOW);  
    }
}