Explore the first lecture of MINICOURSE 3 on combinatorics of squared surfaces and geometry of moduli spaces, part of the AGRA IV (Arithmetic, Groups and Analysis) series. Delve into advanced mathematical concepts presented by renowned speakers Carlos Matheus and Vincent Delecroix from Ecole Polytechnique/CNRS and Bordeaux/CNRS, France. This 54-minute lecture offers a deep dive into the intersection of combinatorics and geometry, providing valuable insights for researchers and advanced students in mathematics.