In order to build information systems, project managers concentrate on the system to produce but also on the engineering process. Each process is necessarily different for each situation as it depends on the targeted information system. Process modelling is an important step towards information systems quality. Nowadays, method engineers are faced to a lot of different process models; however, they need to adapt them to the organization specificities which is hard to achieve. We propose a method allowing method engineers to build process metamodels to instantiate the process models that meet the actual organizations constraints and specificities. Our method consists of selecting the concepts needed from a conceptual graph, gathering the current knowledge of metamodelling concepts for information systems engineering processes, and integrating them in a new process metamodel. In this paper, we focus on the concepts selection. We also present ProMISE, a tool that supports our method.