If you have git installed on your machine, then open a terminal and just run :
git clone https://github.com/ClementNerma/NightOS.git
To install the last version, just download this repository or click here : https://github.com/ClementNerma/NightOS/archive/master.zip https://github.com/ClementNerma/NightOS/archive/master.tar.gz
On Windows, just go into the extracted folder and run night.bat. On Linux or MacOS, run night.sh
This project is under the license Creative Commons Attribution 4.0 International - No commercial - No derivative terms (see more at http://creativecommons.org/licenses/by-nc-nd/4.0/)
I'm not responsible for any damage caused to your computer by NightOS, including data lost, bugs, etc.
NightOS documentation and roadmap are available here