Help only half my mods work

Hello Reddit, so I’m trying to mod my game, and half of them don’t work. My younger brother is more tech savvy and he says the “package files” (the ones with little paper icons) won’t work. But the specific ones that say “sims 3 custom content” do work. All of them are in the override folder, so I’m not sure what’s going on. They aren’t in the lil menu you get when you open the game, and my brother thinks maybe I have too many? Idk. Help please