First, you have to make it clear whether there is a CAN-BUS (what is can-bus?) built-in your car.

If that question is clear, then follow the instruction as below:

IF WITH CANBUS, THEN JUST PLUG AND PLAY.

IF WITHOUT CANBUS, THEN PLEASE CONNECT IN THIS WAY: OUR SYSTEM STEERING WHEEL CONTROL HAS 3 LINES, ONE IS KEY1, ANOTHER IS KEY2, THE THIRD ONE IS BLACK COLOR GROUND, PLEASE CONNECT KEY1 TO THE STEERING WHEEL CABLE FROM THE ORIGINAL CAR, AND CONNECT THE BLACK CABLE GROUND TO THE GROUND OF THE CAR, IGNORE THE KEY2.