Mina Himwich, a physicist from Princeton University's Princeton Center for Theoretical Science, opens a two-part introduction to celestial holography as part of the Institute for Advanced Study's 2026 Prospects in Theoretical Physics summer program. This first session lays out the basic framework: how gravitational scattering amplitudes in asymptotically flat spacetime can be reorganized as correlators living on a celestial sphere at null infinity. Himwich walks through the asymptotic symmetries and soft theorems that motivate the celestial approach, connecting them to the broader holographic principle familiar from AdS/CFT but adapted to flat space. The talk is aimed at graduate students and researchers already comfortable with quantum field theory and general relativity, building the formal machinery step by step on the board with minimal flash. It sets up the technical groundwork for the more advanced constructions expected in the second part of the series.