RAD7 is a multifunctional instrument that serves as the foundation for a comprehensive radon gas testing system. It can be operated in different modes and used for various purposes. This manual adopts an advanced approach, which starts with a simple step-by-step description of how to obtain a) real-time monitoring and b) readings for inhalation experiments. Next is a detailed introduction to the various features of the instrument and how to use it. The remaining chapters of the manual include a series of topics, and their order may be somewhat arbitrary. We suggest that you read this manual as thoroughly as possible to understand the entire operating procedure. Although RAD7 can measure the required data well on your day, it may take several years to master the subtle changes in radon and thorium gas and understand the full functionality of the instrument.