UPDATES9 August 2019: adding of a section on configuration of the navigation stack parametersOverviewLocalization, mapping and navigation are fundamental topics in Robot Operating System (ROS) and mobile robots. However, it is very complex to learn. Usually, beginners find it difficult to even know from where to start. The typical tutorials in ROS gives high-level information about how to run ROS nodes to performs mapping and navigation, but they do not give any details about the technical aspects. Some other courses focus more on the technical aspects, which is mathematically complex, but does not give a clear link to how these concepts are tied with the ROS navigation stack. This course addresses this gap and follows a practical approach to introduce new learners to mobile robots navigation foundations and how it is implemented in ROS. The course is designed to introduce you to the world of mobile robot navigation in a quick and effective manner. In this course, I presented a detailed coverage of the most important package in ROS for navigation: the tf package! Without understanding this package, it will be difficult to deeply understand how navigation works in ROS. Although there are tf tutorials, tf package heavily relies on important theoretical concepts not presented in ROS tutorials. This courses provides a systematic introduction to the necessary theoretical background and complement with demonstration and programming activities of the tf package utilities and API. This course assumes that you have some background on the main concepts of Robot Operating System (ROS), such as ROS nodes, ROS topics, ROS services, and an understanding of the basic notion of motion with ROS. If you do not have these skills, them I would recommend to first enroll to my course ROS for Beginners: Basics, Motion and OpenCV to get the necessary background.  My experience with ROSI have been programming with ROS for many years both in academic and industrial projects. I am very passionate to develop program with ROS. I have also been teaching ROS at the University and providing training programs. I am R&D Director of Gaitech Robotics, and I have developed many ROS packages for robots and drones. I have been leading international scientific activities around ROS, and in particular, I am the editor of three volumes of books with Springer entitled Robot Operating System, The Complete Reference. I gained a lot of experience on what difficulties new users encounter to learn ROS and this contributed to pin right to the point addressing these problems through the different lectures of the course.