Digital Twins are now recognized as a promising technology to attain better reactivity, flexibility, even resilience of manufacturing systems. Due to its monitoring and forecasting capability, a Digital Twin could be a wonderful advantage offered to Industry5.0 systems. However, none of these envisioned capabilities is achievable without a proper way to ensure that the Digital Twin model is always a correct replica of the system of interest, i.e. that it keeps being synchronized with its physical twin. However, this synchronization process, which is essential and is the heart of the digital twin connection to the real world, has been barely studied in the manufacturing system’s literature. If general methods exist to implement synchronization, they always stay at a conceptual level and do not present a practical guide to implement it. This paper is thus written as a first step towards a formal methodology going gradually from the requirements of synchronization to the synchronization actions needed at the Digital Twin level.