Chose to create a new household or add a household from the library. Install the mods and then start a new game with the custom world. I use three NRAAS mods to do this: Mover, MasterController, and Story Progression. Let’s say you download a custom world from somewhere that does not have any Sims and you want to quickly create a thriving town. Populate a world with Sims from another world.Re-populate a world that comes populated with Sims.Described below are three methods for populating a Sims 3 world: