Visit the original article here: https://www.3dartviz.com/skills/skills-tech/programming-video-game-interaction-cpp.html#one-page-designDocument
The goal of the One Page Design Document is to visualize the whole game’s logic in only one concise surface. Ideally you print it on paper and the team writes or draws on it later. I am defining the interaction patterns in the game, using the prototype level's gameplay as a template. This helps you decide what to write in C++ and what in Blueprints. You only write C++ code for objects that share classes in all levels.