If you have an intel mac and enough disk space I would strongly recommend using Boot Camp and installing windows natively. VirtualBox was highly unreliable in my experience, and if you're messing about with talking to your car you really want stability.
You can download a windows ISO here: https://www.microsoft.com/en-gb/software-download/windows10ISO
You don't need a product key as its free to use if you don't want to customise it.
Just run Boot Camp and give it the ISO and it should do everything for you. After windows is installed it will pop up a dialog to install the boot camp drivers - just click Next until it completes.
After it's done it will boot straight into windows every time, which is annoying. You can fix this by rebooting and holding the option key until you get the boot menu, select the macOS disk to boot into macOS. Then when you're back in macOS, go to System Preferences -> Startup Disk, unlock the pane and select the macOS volume, then click back to come out of that pane. Then it will default to macOS on startup and you can boot into windows by holding the option key.
Once you've got windows installed give me a shout and I'll chuck you the driver bundle.