This open access book is a practical guide to experimentally understand, analyze, and optimize the performance of 5G networks. It is organized as a series of simulation projects supplemented with the underlying theory, to help readers learn various aspects of 5G through hands-on simulations using NetSim. It therefore accomplishes two things simultaneously: It explains 5G networking and shows how to unlock the power of the NetSim simulation environment. Commercial deployments of 5G are well underway, covering at least a third of the world’s population. With such widespread use, engineers and researchers need tools for design and development of the 5G protocols, rapid prototyping, scalability testing, and research into complex network interactions. Simulators are often their first choice; they are cost effective, flexible, and easy to use. NetSim is an industry-leading network simulation software used by over 400 organizations in more than 25 countries. Researchers and engineers worldwide rely on NetSim for R&D and for developing 5G-related products. This book builds on that ecosystem by providing readers with structured, hands-on projects that demonstrate exactly how NetSim can be used to model, test, and optimize real-world 5G scenarios. By working through these simulations, readers gain both a deeper understanding of 5G technologies and practical experience using one of the most widely adopted tools in the field.