To get Red on your machine, simply download and save the latest stable version that corresponds to your operating system (OS) from here: http://www.red-lang.org/p/download.html. The download is named red-num (on Windows, the file also has an .exe extension), where num is the version number, such as 063. This small file (around 1 MB) contains the full Red toolchain, runtime library, and console source code, truly batteries included! It is that small because no external dependencies other than the OS are included.
On the downloads page, you can also find the nightly automated build and the latest source code from the master branch. If you want to work with a Red version that has the latest functionalities, download the nightly master build. For regular development, you better stick with the last stable version.
Red's runtime library is written as a mix of Red...