The aim of this paper is to show how we can design a serious game and implement it. For this purpose, we propose a conceptual framework (a meta-design methodology) structuring the design of a serious game. Our conceptual framework is based on six independent yet complementary facets (or aspects) involved in the serious game development: the domain modelling (or domain simulation), the specification of learning objectives, the definition of interaction rules (or game rules), the level design and difficulty progression, the decorum description and the deployment of the game in an operational environment. They define a common language to improve communication and discussion between the stakeholders involved in the design and the serious game honing. Secondly, we have built a software framework for constructing serious games according to our conceptual framework. It aims to provide two main architectural requirements: reutilization and maintainability. We shall see what our design choices are and which solutions have been found according to the underpinning conceptual tools. We want to give a deeper understanding of our idea of a serious game by presenting a technical view of the design. We will give a thread example: a serious game (SpaceBidule) conceived in our laboratory.