Simon Caron-Huot of McGill University opens a two-part lecture on Lorentzian conformal field theory, delivered at the Institute for Advanced Study as part of the 2026 Prospects in Theoretical Physics summer program on celestial holography. He works through the analytic structure of CFT correlators in Lorentzian signature, covering operator ordering, causality constraints, and the analytic continuation techniques that connect Euclidean correlators to physical, real-time observables. The talk builds toward tools used in celestial holography, where scattering amplitudes in flat space are reorganized as correlators of a conformal field theory living on the celestial sphere. Aimed at researchers and advanced graduate students already comfortable with conformal field theory and scattering amplitudes, the lecture is blackboard-style with Caron-Huot working through derivations step by step rather than presenting polished slides. It sets up the technical machinery that the second part of the series will apply directly to celestial amplitudes.