I fear I am not really a big help there. Usually I thought mods to Steam games are simply applied by first installing the base game and then some sort of modifier application that lets you include mod packs.

Here is a video calling out mod managers for Skyrim, I think:
https://www.youtube.com/watch?v=x6dFoAkUV1M

Much success and much joy with your "The Elder Scrolls" questing experience, Whitey.