First Go

Hi, I'm new to all of this and I've edited the blink file to have more LED's and I've set it up with all the short pins going to ground and then the other pin going into 13,12 and 11. The problem is that the LED in pin 13 is extremely bright and the rest are not bright at all. and when I switch around the LED's its still the brightest on pin 13

What do I do to make them all the same brightness?

void setup() {                
  pinMode(13, OUTPUT);
  pinMode(12, OUTPUT);
  pinMode(11, OUTPUT);
}

void loop() {
  digitalWrite(13, HIGH);   // set the LED on
  delay(1000);              // wait for a second
  digitalWrite(13, LOW);    // set the LED off
  delay(1000);              // wait for a second
  
  digitalWrite(12, HIGH);   // set the LED on
  delay(1000);              // wait for a second
  digitalWrite(12, LOW);    // set the LED off
  delay(1000);              // wait for a second
  
  digitalWrite(11, HIGH);   // set the LED on
  delay(1000);              // wait for a second
  digitalWrite(11, LOW);    // set the LED off
  delay(1000);              // wait for a second
}

Have you any series resistors? - You need them.
Are the LEDs all the same colour? - different colours have different brightnesses for the same current.

solved it by putting 3 330ohm resistors in