This report details the implementation of an experimental platform that will be used in order to study how humans understand complex systems / situations. It implements a microworld as well as a scenario building tool that facilitates the development of a range of scenarios using a common platform. A user guide of the platform is first provided in this report. It describes how to use the user interface that enables interaction with the situation and how to configure its various parameters. The scenario building tool is also presented. It allows adding data structures to a scenario that will enable/disable associated functionalities. It exploits a simulator that was built as part of the IMAGE project in order to simulate system dynamics, the formalism that was chosen to represent a complex situation. Finally, additional technical details are provided in the appendices.