This European Standard presents methods which are divided into four main categories:1)scope and scenario description;2)process description;3)data;4)system architecture.For scope and scenario description, the modelling methods are based on Unified Modelling Language (UML) Use Case diagrams. The process descriptions are done using Simplified Activity diagrams. Data modules are described by Express G diagrams. Rules and constraints are described via Express-Where-Rules. Further descriptions, for example, for a data dictionary, are based on tabular forms. To support the development of a system architecture, the modelling method of UML Package diagrams is used.