How can I read console input? (receife data from console)

Using Arduino Project Guidance
#1

English:

How can I read a console input into a variable (receife data from console with arduino uno)

Thank you.

German:

Ich finde einfach keinen weg wie ich eine Konsoleneingabe auslesen kann.
Ich möchte etwas eingeben welches dann in eine Variable kommt

Bitte um euere Hilfe!

Im voraus schon einmal danke.

#2

See Serial input basics

#3 
int RELAY1=13;
void setup() 
{
  Serial.begin(9600);
  pinMode(RELAY1,OUTPUT);
}
void loop()
{
  int val = Serial.read() - '0';
  if (val == 1) { // test for command 1 then turn on LED
    //Serial.println("RELAY on");
    digitalWrite(RELAY1, LOW); // turn on LED
    Serial.println("led off");

  }
  else if (val == 0) // test for command 0 then turn off LED
  {
    // Serial.println("RELAY OFF");
    digitalWrite(RELAY1, HIGH); // turn off LED
    Serial.println("led ON");
  }
  Serial.println("Arduino program");
  delay(500);

}

I have added example code. With this code you can send 0&1 to turn On/OFF the LED

#4