If you haven’t updated Sims 4 for a while, it could have stopped supporting mods. Make sure the downloaded mod version corresponds with your current game version and that you’ve made the necessary game updates. This can usually be done on the mod’s download page. If the steps above don’t alleviate the issue, you may need to check the mod compatibility. The folder will unzip automatically in the same main folder. If they’re in a compressed folder, double-click it.
