Check the scheamtic below and have it in front of you when you make the connections. Is very simple. The Arduino is connected to the stepper driver and this driver to the motor. To receive data we connect the HC05 Bluetooth module on pins D11 and D10 where we will create a software serial port. We also connect a buzzer for sound notifications. We supply the Arduino on the Vin pin with 12V and the driver as well with 12V for the motor. The driver also needs 5v supply. Supply 5V to the hall sensor and connect it to the analog input of the Arduino That's it.