Autoradio Chevrolet Aveo

When I was 67 years old, I bought a Chevrolet Aveo, 5-door, 1.4 l with manual air conditioning. It’s an EU import. The car corresponds exactly to my ideas, and it has everything I expect from a car as a pensioner. I don’t want to say that it’s a typical pensioner car! I like the exterior appearance. The boarding is comfortable for me (although 195 cm!) because the seating position is relatively high. For consumption I can because of the short d The air conditioning system is switched on automatically as soon as the ventilation controller is turned towards the front window. Switching off is only possible in the other control positions. In the car a serial radio is installed. I would like to have the turn-on volume controlled louder with this radio, but do not know how to do it. The operating instructions do not provide any information about this. When the radio is switched on, the It’s so quiet that it always has to be re-adjusted. Every time the ignition is switched off, there is a new problem. The visit of a Chevrolet workshop and the attempt of a fitter to solve the problem was not successful. He felt that it had to be done, but could not – no experience. The radio type is apparently still too new. Can someone help me and explain to me how to do it. I thank you in advance. Many greetings: Chevroletopa