a question to electronics builders, or who else knows!

I want my laptop from his stereo-out to my Boseradio (gamma CC Bj. 92) via its changer input, so that I can access it via the mode button.
So I have heard the advice with the adapter cassette a thousand times; but it should look like something, because my laptop finds space in my glove compartment and I operate it with a separate touchscreen (there are no cables flying around = they are all hidden)
Would be great if someone could tell me something and say thank you in advance.
Greetings Flo

