Learn hands-on numerical simulation techniques for light and cold atom systems in this first lecture from Johannes Schachenmayer of Université de Strasbourg, delivered as part of the IV School on Light and Cold Atoms at ICTP-SAIFR. Explore practical computational methods and numerical approaches essential for modeling quantum systems involving ultracold atoms and their interactions with light. Gain foundational knowledge in simulation techniques that are crucial for understanding and predicting the behavior of these complex quantum many-body systems through direct computational experience and theoretical insights.