This deliverable presents the intermediate version of the TREASURE training materials on Thermal Energy Storage (TES), with a particular focus on Pit Thermal Energy Storage (PTES) for district heating applications. Developed and applied in university teaching, the material provides a comprehensive overview of TES technologies, covering design and construction principles, system integration in district heating networks, thermal performance analysis, simulation approaches, and economic evaluation. By combining theoretical foundations with practical exercises and case-based analyses, the deliverable supports knowledge transfer and capacity building for large-scale thermal energy storage in sustainable energy systems.