[Prerequisites] Mac OSX

First of all, install XCode and the Apple Developer Tools you're running on your Desktop/Laptop Mac system. Once done, download the x86 v0.10.38 node binary distribution from :

https://nodejs.org/dist/v0.10.38/node-v0.10.38-darwin-x86.tar.gz

and once extracted in your favourite folder, insert it in your system PATH by editing the hidden ~/.bash_profile file :

NODE_PATH=<path-to-node-binaries>
export PATH=${NODE_PATH}/bin:$PATH

you now have to install globally in your system two required node.js modules by means of the npm tool. So, run :

$ npm install -g grunt
$ npm install -g grunt-cli

then create a custom work folder and clone into it the three main repositories of ArduinoStudio :

$ git clone --recursive https://github.com/arduino-org/ArduinoStudio.git
$ git clone https://github.com/arduino-org/brackets-shell.git -b master
$ git clone https://github.com/arduino-org/brackets-arduino.git

and you're done ! The preliminary steps are over !