There is a lot of information to learn in Baldur's Gate 3, but above all else, it's important to understand the basic foundational mechanics of the game. Because BG3 is based on Dungeons and Dragons Fifth Edition, it features a similar approach to turn-based combat. The simplest explanation of the Action Economy in BG3 is that it determines what players can do in a round.
Baldur's Gate 3: Action Economy, Explained
The Baldur's Gate 3 Action Economy is essentially how much players can do in a round of combat – here's a more in-depth look at each action type.