The large number of systems offered on the market makes a well-founded selection process from requirement collection to final selection necessary. A comprehensive model that systematically supports and simplifies this process is the subject of the following article. The methodo-logy goes beyond a questionnaire-based query and validates system capabilities using structured case studies. The first part of the article describes the process steps from the survey of the requirements of the system to their structuring in customer specifications. The second part of the system selection process is described in detail in the second part of the article.