Your computer is a bunch of parts that need software to make them work. The "operating system" handles talking to the hardware directly, while the programs you run only talk to the operating system. Talking to the operating system is easy, talking to the hardware is difficult, since you may need to speak a hundred different languages to work with every possible network card, sound card, graphics card, etc.
The operating systems you have probably heard of are windows and macOS. Linux is a 3rd one.
Windows is owned by Microsoft, macOS is owned by Apple, and Linux is developed by the community and (typically) released for free. Since anyone can work on Linux, there are tons of different versions of it floating around, that are all slightly different from one another.
There are low powered FM transmitters you can get for your car
FM transmitter plugs into cigarette lighter for power
iPod connects to FM transmitter via AUX cord
You tune your cars radio to whatever frequency the transmitter is set to, and it plays whatever your iPod is playing