Hello and welcome back. I will try and assist you with your question.
HERE is the official web site for your programmer.
HERE is about the best price I have found. It may be possible to find a cheaper one on Ebay but I do not suggest buying a used one.
The power puck installs between various sensors on the engine. It takes the input from some sensors and "adjust" the output signal to the PCM. Then takes the PCM outputs and "adjust" them to the engine. This will change the fuel and timing curves to increase horsepower and torque.