The following instructions tell you how to install the Arduino IDE.
For Windows see the following links:
Note : The delivered Arduino Nano may not use usual FTDI serial USB driver but a Chinese driver instead. Download and unzip the driver file package from the link below. Then plug the Nano and find the peripheral USB Serial 2.0 in device manager, right click on it and update the driver by choosing the directory where is located the unziped .inf file. Remain the COM number to select later in IDE. http://www.wch.cn/download/CH341SER_ZIP.html