In your computer folder system, go to your Steam folder and inside it find the folder SteamApps\common\Skyrim\Data.The only files you need are the esp and the bsa.
If you have not had Vilja installed on your computer previously, you don't need the folder called scripts. The newly created folder should contain one esp-file, one bsa-file, a readme and a folder called scripts. Otherwise, she may not follow you properly. Make sure your character is not already inside The Bannered Mare when you install Vilja.
