Last but not least, you need the Resource.cfg file in your Mods folder to make every mod work in your sims3 game. Both of these folders could be found in 'My Documents'. simpacks should go into the 'Download' folder, and package files should go inside the 'Mods' folder. However, the dashboard mod only identifies package files so be aware of that. The custom contents come in simpacks or package files.
Some custom contents might crash the game or lag it to oblivion, therefore this mod is very useful. You can download it in 'modthesims' site, and the beauty of this mod is that it tells you which custom content has gone corrupt, which mods clash with each other, etc.
Also, if you download custom content, I'd strongly recommend you one of the sims3 mods that is called 'dashboard'.
