To install the software is necessary first to download the binary file from Arduino website ( http://arduino.cc/en/Main/Software ). After the download, the binary should be execute and the IDE should be installed.
The IDE is the program used to write code for the microcontroller. It may seem a little daunting at first but once you have it installed and start playing around, all its secrets will reveal themselves.
The chapter “A Small Programming Primer” has a general intro to the programming language of the kit. The language has a lot of similarities to the C Language.