This paper describes a way to build a conceptual model for diversified purposes of modelling Enterprise Architectures (EA). It is commonly known that, due to the complexity, Enterprise Architectures need to be considered from several viewpoints. This provokes an integration problem: how to ensure that parallel EA models are consistent. We believe that the best way to solve this problem is to build a generic conceptual model (or an ontology) that is based on the purpose and needs of EA modelling rather than on the metamodels or modelling techniques of the prevailing (viewpoint-specific) domains of EA modelling. In other words, instead of aggregating existing sub-domains of EA we should try to find the core concepts through analyzing the EA domain as a whole. We emphasize the importance of the process through which the conceptual model is produced. Therefore, besides the conceptual skeleton and its utilization we provide an in-depth description of the modelling process we have developed and applied.