: Organizations require material resources, human resources, and business processes to produce goods and services. There is an available market for material resources as well as human resources. The key problem is however the availability of business processes. This paper discusses the development of the requirements for the process assembler, a system that we are going to develop, that will support its users to carry out the key activities regarding business processes. Furthermore, the paper introduces the heuristics for a process selection tool that guides the selection of a development methodology. The process assembler development process is then applied using a prototype of the selection tool, based on those heuristics. The prototype then provides guidance for selecting a suitable development process.