let's beginning with Arduino

The Arduino Project was developed out of an educational environment and is therefore great for newcomers to get things working quickly.
It is a Multi Platform environment it can run on Windows, Macintosh and Linux.
It is Based on the Processing programming IDE
It is programmed via a USB cable not a serial port. This is useful because many modern computers don’t have serial ports anymore.
It is Open Source hardware and software - If you wish you can download the circuit diagram, buy all the components, and make your own, without paying anything to the makers of Arduino.