Before we start creating lots of cool projects with arduino, what is Arduino?
Arduino is an open source, computer hardware and software company, project, and user community that designs and manufactures microcontroller kits for building digital devices and interactive objects that can sense and control objects in the physical world.
An Arduino board is an open-source programmable computer hardware, which is basically an easy-to-use version of a microcontroller. There are hundreds of versions of the board and literarily thousands of Arduino compatible sensors and breakout boards.
Microcontrollers are so complicated to deal with. There are always so many different kinds with different unique ways to program and interact with them. Arduino is here to fix that. I myself had never done any form of microcontroller programming, but with two 5 minute tutorials on youtube, I started working with Arduino.