Steering wheel control (SWC) to RPi head unit

Hi all

I am a complete noob to this sort of thing so apologies if I don't make sense or if I have posted this in the wrong section but I need your help!

I have a RPi in my car which has replaced my head unit. Everything is working great but I want to be able to use my steering wheel controls with it.

I am using OpenAuto Pro which has keyboard commands to be able to do things, e.g. Q key will pause the song.

I have looked at many videos of using an Arduino to receive the CAN signals of the stereo, read them and send them out as keyboard commands to the RPi.

The question/issue I have is a lot of the videos I see use (what seems like) a single CAN wire. In my car, on the stereo harness adaptor I have a CAN high and CAN low.

How can I use both of those wires in to an Arduino, and then have that Arduino send out keyboard commands to the RPi?

Again, sorry for my noobness and thanks in advance for your advise!