This chapter introduces to blockchain concepts introduces basic concepts of blockchain and its structure and discusses the benefits of blockchain. This chapter serves as an introduction to blockchain technology, highlighting its core principles and applications, particularly in the healthcare industry. The chapter begins with an overview of blockchain, tracing its origins from the financial sector to its adoption in healthcare and other industries. It explains the fundamental structure of blockchain, detailing how blocks, nodes, hashes, and consensus mechanisms work together to form a decentralized and secure ledger. This chapter emphasizes the benefits of blockchain, including decentralization, improved data security, transparency, and trust, while exploring its role in improving healthcare operations. A case study focusing on healthcare applications of blockchain illustrates how blockchain can revolutionize medical records management by ensuring data integrity, security, and patient autonomy. The chapter concludes by introducing key challenges, particularly regarding sustainability and energy consumption, and offers exercises to help the reader apply blockchain concepts in real-world scenarios.