All you need to do to make the LED blink more quickly is to change the number inside both delay()  functions from 1000 to 250. Upload the following code to your Arduino to see this in action.

void setup() {
  pinMode(13, OUTPUT);
}

void loop() {
  digitalWrite(13, HIGH);
  delay(250);
  digitalWrite(13, LOW);
  delay(250);
}

Simulator: https://tinkercad.com/things/8gFYI6jc4kY