There are many ways you can write code and work with M2. One of the quickest and easiest ways is to use the Arduino IDE (Integrated Development Environment) which is what this documentation will use. Many other development environments work well including Atmel Studio and Simulink®.
It is ok to do some initial setup before you have an enclosure, but before your M2 spends long periods in the car please consider protecting it. We have a few configurations of enclosures designed and ready for 3D printing. You can download the designs, tweak them as needed, print, share, lather, rinse, repeat.