Hello I wanted to change my radio in the smart, it has never changed a car radio and I am a bit overwhelmed. There was zb a wire harness which I marked red loose in the car so not connected to the radio for what is it ?? I marked the wire harness and need for the new I think a 20 pin adapter or ? For the green and blue wire harness ? For the antenna cable I also bought an adapter, hope it is the right one. But now I did not think about the yellow marked cable which has a blue plug, what has it got on it with it and how do I get the new radio? Or is it not important? Later also wanted to put a back camera on it which was important if it is. Would I be happy about answers The adapter I ordered https://amzn.eu/d/7793RDOhttps://www.ebay.de/itm/202016729349?… With the new radio was still there, please tell me that I need to connect/sold