ECTS stands for the European Credit Transfer System. The Master's program involves a total of 120 ECTS credits.
One module can include up to three courses focusing on a closely-related subject. There is an exam at the end of each module. The program has a total of 14 mandatory modules. The module handbook (in German) in the download section shows you how the program is structured and provides details on each module.
Each semester contains 30 credit points (CP), equivalent to a 900-hour workload. Each credit point involves a 30-hour workload and includes attendance, preparing and reviewing course content, preparing for exams, reading related literature, writing papers, giving presentations, developing projects, etc.
More information on the modules and the ECTS can found in the download section.