I am completely new to the universe of hardware and I am trying to control 2 motors via my RPi 4.

But the 1st step is to find out which electrode is positive and which one is negative so when connecting to a stepper motor controller, I won't burn/damage it.

I have a [toy car][1] which I bought from Kmart and here is its [manual][2].

I have opened its shell and try to figure out how to connect my RPi 4 to the 2 motors on this car.

After research, my understanding is I need to connect RPi 4 to a stepper motor controller first and then connect to the motors.

Here are the photos.

[![car][3]][3]

[![cables][4]][4]

[![circuit][5]][5]

[![Rpi4][6]][6]

[![battery][7]][7]

[![controller][8]][8]

[![motor][9]][9]

[![turn][10]][10]

As you can see here, there are 2 motors, one is to control drive or stop, another is to control the turning.
There is no manual to the 2 motors.

So here is my questions:

1. How can I tell which electrode is positive and which is negative on both motors? 

2. What are the 3 things I marked in picture 2?


  [1]: https://www.kmart.com.au/product/radio-control-2.4g-hot-rod/3630819
  [2]: https://www.kmart.com.au/wcsstore/Kmart/pdfs/43022366_Manual.pdf
  [3]: https://i.sstatic.net/ORDzx.jpg
  [4]: https://i.sstatic.net/GWHgk.jpg
  [5]: https://i.sstatic.net/KwLkp.jpg
  [6]: https://i.sstatic.net/lwOQY.jpg
  [7]: https://i.sstatic.net/yCTe0.jpg
  [8]: https://i.sstatic.net/v8x6E.jpg
  [9]: https://i.sstatic.net/mmzO8.jpg
  [10]: https://i.sstatic.net/84TzU.jpg