To use MC Command Center (MCCC) in The Sims 4, first download it from the official site (deaderpool-mccc.com) and unzip the files into your Mods folder (Documents > Electronic Arts > The Sims 4 > Mods). Make sure "Script Mods Allowed" is enabled in your game settings. Once installed, click on a computer, Sim, or mailbox in-game to access the MC Command Center menu. From there, you can control things like pregnancy, population, aging, cheats, relationships, and more. It's a powerful tool for customizing gameplay and managing your Sims’ world with detailed settings and automation.