Stepper motor, LED, Light sensor

Hello everyone,

I tried to make a LED blinking and at the same time a Stepper motor turning. I got both in one loop, but the program goes in the loop only 1 time. So it blinks once and then the motor turns one.
Can you help plz with a solution.
This is my code... and thanks in advance

#include <Stepper.h>

Stepper Motor(1024,2,3,4,5);
int Lightsensor = A0; // Analogen Eingang 0 als Analog0 definieren
int Brightness = 0; // Variabel helligkeit auf 0 setzen
int Limit = 10; // Grenzwert hell-dunkel

void setup()
{
Serial.begin(300); //Serial-Übertragung auf 300Baud-reicht völlig
pinMode(10, OUTPUT); //Digitaler-Ausgang 10 für LED-Ansteuerung
Motor.setSpeed(10);
}

void loop()
{
Brightness = analogRead(Lightsensor);

if (Brightness < Limit)
{
digitalWrite(10, HIGH);
delay(50);
digitalWrite(10,LOW);
delay(50);

Motor.step(100);
delay(100);

Motor.step(50);
delay(100);

Motor.step(100);
}

else
{
digitalWrite(10, LOW);
}
}

(I have asked a moderator to move this to Programming where it belongs. It is not about education is it?)

I see nothing obviously wrong with the program, which leaves the possibility that your wiring for the motor is wrong - and it takes so much current that the Arduino goes in a bad state. Do you power the motor through some transistor/mosfet/driverchip or directly of the Arduino pins?

I see nothing obviously wrong with the program

Except for all the delay()s.

Serial.begin(300); //Serial-Übertragung auf 300Baud-reicht völlig

Why is this in your code, when there are no Serial.print() statements? Conversely, why are there no Serial.print() statements, to see what the code IS doing?