Using this facility will help you to obtain an understanding of what ESP-r can do and how it works. You will learn how to define a model, simulate it and analyse the results. You will also get an impression of the types of design issues that can be assessed. If you do not understand a term, do consult the ESP-r glossary (the link is above this text). If you conclude that ESP-r is worth a try then you should consider joining the users' club.