fade effect - 2 push buttons

Projects Programming
5

You also need to use his code in loop() just as it's written

void loop() {
  if (digitalRead(UP_BUTTON_PIN) == LOW  && brightness < 255)
    brightness++;
  if (digitalRead(DOWN_BUTTON_PIN) == LOW  && brightness > 0)
    brightness--;
  analogWrite(LED_PIN, brightness);
  delay(20);  // About 5 seconds from full off to full on
}