High-Performance Computing (HPC) clusters are used for large scale data processing and data analysis, fine grained parallel calculations and simulations of ever increasing fidelity. This course material is meant to introduce learners to the core principles behind the using the HPC clusters HEMERA at HZDR, how to connect to it, how to dispatch jobs and retrieve their results, and how to program applications that can harness the full power of this machinery. This is a joint workshop organized by FWCI-H at HZDR and Scientific Compute Core at CASUS.