This folder contains a Jupyter Notebook named CostCalculator.ipynb, you can browse it via GitHub to review the logic, or to actually run the notebook live you can download it and run it in any Jupyter environment with Pandas installed.
The easist way to do this is to go to the getting_started folder and deploy that CloudFormation template, it will create a Notebook Instance for you with this folder included. From there simply follow along with the notebook!