The main principle in International and Swedish crisis management is collaboration between emergency services (police, fire brigade and ambulance service). Collaboration is a complex concept and a number of studies show that many practical problems during crisis management can be attributed to problems related to how the collaboration is organized and implemented. One way to train how critical events should be handled is through live simulation exercises. The authors have developed a validated live simulation model to improve collaboration between emergency services. The live simulation model is developed within the framework of the project Safety and Security Test Arena in Sweden. The model focusses on learning for the participants and is based on theories on learning, previous research on collaboration and live simulation together with professional experience from conducting live simulation. The model includes preparation, acting in scenarios and structured reflection seminars. In this paper, the preparation phase is in focus. A digital preparation material has been developed to support learning before and during the live simulation. The preparation aims to develop knowledge about equipment, tasks and needs of the other services as well as knowledge on functional collaboration. The preparation also aims to create a good learning climate and better conditions for learning from participating in the scenarios of the live simulation. The digital material is an interactive material, which includes instructional films from each emergency services, structured reflective questions, short lectures from researchers on collaboration and live simulation knowledge. The digital preparation material has been tested, evaluated and further developed in two collaboration live simulations. After each live simulation focus group interviews were conducted with both participants and instructors. The result showed a need to increase the interactive elements of the digital preparation material in order to stimulate active discussion and reflection, which are central theoretical bases for the model.