What is the Arduino ? The Arduino is a programmable microcontroller that can be programmed to perform simple tasks on its own and when connected to electronic circuits and breadboards. It is a fun way to get into combine programming and electronics projects.

Arduino_Uno-R3 This is the most common type of Arduino, the Uno version 3. It has memory space for your programs even when switched off. Turn it on again and your Arduino swings into action carrying out your instructions. It has an on-board USB connector through which it can be programmed. The Uno can read & write electronic signals through the various I/O pins. It can run off a 9v supply or when connected to a PC’s usb connector it can take power from that.
There are a number of add-on kits which can piggyback onto your Ardino to carry out other tasks, these are called shields.

Here is very quick demo of a 2 Line LCD display shield piggybacked onto an Arduino UNO running some simple code to write text to the display.
Miniature Organic led emitting diode or Oled being controlled by an Arduino Nano clone

Oled screen with Arduino Nano