New MODS need to be retyped, and some MODS need pre-files. If you are sure that the available MODS just don't work, or if you put them in, you need to pre-file. If you are not sure about the available mod, or don't have a pre-file, try not to download it online. It's risky. You'd better go to the Q group of specialized MODS, where there are many MODS, which are safer than downloading by yourself, and there are tutorials.