After the ontological design of an organisation, this design must be made operational. The bridge between the ontological design of an organisation and its being operational consists of four phases. The first one is engineering (or implementation design). It comprises the selection of proper technological means for the elements of the ontological model. The second phase is the actual implementation, that is, the assignment of concrete technological means to the elements of the ontological model. After this phase come installation and operation. Installation is about the specific assignment of technological means, depending on time and space. Operation starts when the ‘on button’ is pressed. A special section is devoted to (hierarchical) organisational structures as opposed to ontological structures.