The most important regulations for you are probably the study plan. This regulates all the basic aspects of studying (grade weightings, repetitions, postponements) and is therefore a good place to start. If the paragraphs seem too complicated, you should definitely take a look at the appendices! These summarise the study programme in a simple and clear table.
The study regulations are based on the Regulations on Studies and Performance Assessments (RSL) at the Faculty of Humanities and Natural Sciences of 1.9.2008.
The University Act (UniG), the University Ordinance (UniV) and the University Statute (UniSt) in turn form the basis of the RSL.