What should i pay attention to before installation?

There are 7points that must be paid great attention to before installation:

1>To a common ground(earth) point
First connect the black ground (earth) lead then connect the yellow and red power supply leads.

2>To the power antenna(ANT) control lead or the power supply lead of the antenna booster
It is not necessary to connect this lead if there is no power antenna or antenna booster or with a manually-operated telescopic antenna from the original car.
But if there is power antenna or booster, it must be connected. If not connected, the radio signal will be weak and there may be no or few stations received.

3>To the parking brake switch cord
Normally it is not necessary to be connected. But for some countries, it is against the rule of law that watching videos while car in motion.

4>To a car’s illumination(ILL) cord
Be sure to first connect the black ground lead to a common ground point.
It is connected to the original car ILL lead correspondingly. If connected, the background light of the unit will be shifted to nigh mode (darker) after the headlight is on. 

5>To the steering wheel control keys(available only for analog signal of steering wheel)
Be sure to first connect to the thinner black ground lead and then connect the keys to original car steering wheel wire.
It depends on original car steering wheel wire about whether to connect one key or two keys
If the original car has one wire, just connect either of them (there is no difference for the two keys)
If two wires, connect both of them (there is no sequence for connection) 

6>To the amplify control lead
It is available only for the car with amplifier. And it is a switch for the amplifier.

If there is no amplifier, it is not necessary to connect. 

7>To the back car lead(reverse camera in)
The lead is for reverse camera signal detection. For connection details, refer to reverse camera user manual.