If you have never used an Arduino, it is recommended you read the Arduino Mega 2560 Getting Started. and the many available tutorials. Just make sure you select Arduino Mega 2560 when selecting which Arduino you have. The Arduino Mega 2560 in the PODuino is just a regular Arduino, and can be used on its own like any other Arduino.
Otherwise, make sure you have the latest Arduino IDE
You need to install the IOTileBridge library (you can find the latest version as a GitHub release).
If you're using the PODuino, go to the Arduino IDE, choose Sketch -> Include Library -> Add .zip Library and select the IOTileBridgeMega.zip folder downloaded from here