connection : connect positive side of led with arduino pin 3. connect one ternimal of motor with arduino pin 5. connect negativer terminal of led with resistance of 100 ohms . connect other side of resistance and other terminal of motor to GND pin of arduino. connect middle pin of potentiometer to arduino A0 pin . connect one leg of potentiometer to 5V pin of arduino and other leg to gnd pin of arduino.
upload the code and enjoy....... :)