To download a mod you want, search the mod here. Then after you download the mod, go to your download folder by clicking computer on your start menu. After doing so, drag the mod to your desktop. Next, click computer on your start menu, then click C:/
then click the Games Folder

next, you need to click the toribash folder youre currently using. When you click on it, you then need to click the data folder
and finally, click the mod folder

and drag your mod from the desktop to that folder.