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If you want to reuse what I've built upon, you will need an STM32-based canbox that is flashable (like the OD-OLO-02). Don't worry about the listed car make since you will be replacing the firmware with your own - all you need to worry about is that the pinout to the canbox matches that of your wire harness. Here (top left) you can see the pinout for the OD-OLO-02.
You are going to need to extend the firmware code to support your own car. Here is an example for my car (Volvo XC90 MY2008). To do that you are going to need to reverse engineer the CAN messages sent on the CANbus (essentially you need to find which CAN ID and bits correspond to things like speed, SWC button presses etc). You can do that with what I linked here, or you might get lucky and find someone who has done something similar for your car. I found a bunch of IDs from googling around.
You will then need to solder connectors to the CANbox PCB and hook it up to a STLINK V2 programmer and flash the CANbox with the new firmware that you have created.
Be aware that while it is quite rewarding, the learning curve can be quite steep if you are new to programming and embedded systems.