Scientific software is in many disciplines crucial for understanding and reusing research data and a cornerstone for reproducibility of research results. The HeFDI Code School adresses the need of especially early career researchers on learning how to create good scientific software and increase the quality of their code for better reusability and sustainability. Together with the colleagues from Suresoft project and NFDI4Ing we offer a series of four workshops. Participants of these workshops will learn methods and techniques to increase the quality of their code, how to produce understandable and therefore reusable code, and to increase the sustainability of scientific software. Workshop - May 12 & Oct 27 - Scientific Software Development is not a Jenga game! Scientific software is often hard to maintain and reuse. A major reason for the instability of software is that it is subject to continuous change. This is especially true for software in the scientific context, since the scientific discourse is open-ended. Change has caused difficulties for scientific software developers from the very beginning, and it continues to do so. In parallel, the software engineering community has produced numerous developments that we as research software developers can take advantage of to significantly support our work. This workshop is an introduction on how to bridge the gap between both worlds and introduces practices, methods and principles to develop maintainable software and to make the software development process sustainable.