Install the Arduino Software
Step-by-step instructions for setting up the Arduino Software (IDE) on your computer and connecting it to an Arduino or Genuino Uno, Mega2560, Duemilanove, Mega, or Diecimila.
What can I do with an Arduino or Genuino board?
If you are unsure on what your first project could be you can try the Arduino and Genuino Starter Kit, it will guide you from your very first steps with electronics into the world of interactive and sensing objects.
Instructions for other boards:
The text of the Arduino getting started guide is licensed under a Creative Commons Attribution-ShareAlike 3.0 License. Code samples in the guide are released into the public domain.