Embarking on the study of finite volume methods and their application to the conservation equations governing fluid dynamics requires mastering certain fundamental concepts. Therefore, this chapter provides an essential overview covering differential operators (notation, definition, and their physical significance), elements of fluid mechanics, generalities and physical applications of differential equations, elements of gas dynamics useful for studying acoustic waves, and finally, basic concepts related to numerical computation. The approach is pragmatic and does not claim to be exhaustive. The aim is to provide the reader with the necessary tools to be effectively utilised in subsequent chapters. From another perspective, this chapter serves as an initial reference for delving deeper into these concepts through the reading and study of more specific texts.