The STESCI activities are divided into six major topics addressing areas of expertise that require input from the scientific community to the PLATO mission and an interface between STESSI and the other work packages. Each work package is divided into several topics corresponding to specific studies to carry out. Valuable models and numerical tools already exist that will provide a first generation of outputs and will serve as a starting basis for building an improved, second generation of relevant models and tools. Activities will continue after launch, based on PLATO data exploitation.