The rapid advancement of artificial intelligence has driven the emergence of data centers as a new class of large-scale loads, often reaching gigawatt levels. This unprecedented scenario poses significant challenges for power system operators, particularly due to the extensive use of power electronics within data centers. Accurate modeling and testing at the electromagnetic transient (EMT) level are essential to ensure system reliability and stability. This speech will present the latest progress in modeling data centers on a Real-Time Digital Simulator (RTDS). The discussion will cover key components such as AI computational loads, chillers, uninterruptible power supplies (UPS), variable frequency drives (VFD), computer room air handling (CRAH) systems, and co-located battery energy storage systems (BESS). A comprehensive example will illustrate the end-to-end process of developing and validating a data center model for real-time simulation, enabling closed-loop testing of control systems. The objective is to provide a practical framework that can serve as a foundation for modeling diverse data center configurations and supporting robust controller validation under realistic operating conditions.