Go to the Arduino tutorial website to get the board file to add to your sketchbook folder, Breadboard Tutorial Site.
You download the file, Breadboard.zip. Unzip the text file, boards.txt. If it is not in a folder called “Breadboard”, then create the folder and move the text file into it.
The photo shows the ultimate bare bones system. Power, ground, and one digital out. Anything less and what is the point.
Please note the cool BoostMicro power supply. It provides a steady 5 volts even as the batteries drain. It is available from Amazon, BoostMicro – Assembled Link.
Step 1: Move the File to Your Sketchbook
The photos shows how this would look on MacOSX and Windows XP.
For more detail: Setup Arduino Software for Atmega328P with Internal Crystal on Breadboard