This deliverable provides a comprehensive description of the Digital Twin Engine Infrastructure architecture. It focuses on the overall design of the system that provides the pillars for both data and compute federations. This includes the requirement analysis of the needs of the scientific communities as well as the requirements coming from a set of highly heterogeneous resources providers. It will detail the different components of the architecture defining the related role and how they will interact with each other in order to implement the digital "continuum" between cloud-edge and multi cloud environments, HPC Centers and Quantum. Policies to access the resources and resources accounting will be also discussed. Finally, it provides a timeline and roadmap toward the implementation of the Digital Twin Engine architecture including the vision for the early testbeds and pilot systems.