Mods aren't installing

[daynagail511]

I am trying to download mods and whenever I look at the properties it says that it's a package file (.package) and opens with Sims3Launcher. Can anyone help me fix it? I have a Mods folder with a Package folder inside and the Resource file.

[Candyd]

Package files don't open with the launcher. Only sims3packs open with the launcher and should go in Downloads contrary to packages.
Put your packages in the Mods/Packages folder while the Sims 3 isn't running ; delete the 5 cache files : CASPartCache.package, compositorCache.package, scriptCache.package, simCompositorCache.package, socialCache.package (these files will regenerate automatically when the Sims 3 starts, so they're safe to delete) ; launch the Sims 3 and it will do the rest.