The Raspberry Pi Model 3 is the latest of the larger boards which boast a powerful 1.2 GHz 64-bit quad-core ARM Cortex-A53 Processor. It features built-in wireless and 1 GB on board RAM. It is currently the most powerful of the credit card sized board.
To get started – you will need the board, 8GB micros SD card and a 5V 2.4A power supply which is usually extra unless you buy a starter kit.
The boards can be ordered from Adafruit, Element14 and Amazon.com. If this is your first foray into working with Raspberry Pi, it is recommended that you start with the Starter Kit from CanaKit and can also be ordered from Amazon, Adadfruit and Newark Element14.
The power supply must not be greater than 2.5A or you will damage the board.
A microSD card with an adapter for a full sized SD card slot will be needed to load the operating system. You can purchase them as NOOB (New Out Of Box ) preinstalled software ready to go – or you can get a blank one and download the image from the Raspberry Pi website
To get started – visit the Raspberry Pi organization website where you will find just about everything you need to get started – http://raspberrypi.org. The Help tab is a good place to start or go to this link https://www.raspberrypi.org/learning/hardware-guide/
Download the image file for Debian Jessie OS here – https://www.raspberrypi.org/downloads/. This page will walk you thorough step by step on how to do this or provide links to more information.
Be sure the check the Community and Forums for other sites that will provide you with additional references and tips on how you can get the most out of your Raspberry Pi