Well that depends on the type of mod you are using. Your best bet would be to read the readme files that are included with most mods. They should tell you the proper way of installing it. I can't tell you the exact way to install just any mod for Morrowind, because the that process differs for some mods. Though here is what I can tell you. -Usually, mods come packed in compressed archives. There are several of these, the most commonly used archive formats are zip, rar, and 7z (7 zip). Use an archive browsing program to extract them. I use IZarc, most people prefer 7zip. -After you have extracted the files, you need to know where your base Morrowind folder is. This would most likely be located at "C:/Program Files/Bethesda Softworks/Morrowind. -If there is a folder called "Data Files" in the mod folder, you can easily place the folder named "Mod Folder" into your Morrowind directory. -If there are folders that go by the name of "meshes", "bookart", "icons", "textures", "sound", "video", "music", "fonts", or "splash", copy those folders to your Morrowind/Data Files directory. -If there is an ESP (or ESM) file, move it to your Morrowind/Data Files directory. ALWAYS read the readme incase there is something you should not do. For example, some mods offer multiple ESP's for different effects, however they cannot be used together or will cause instability in the game. So, always read it, and do what it tells you. Also, after you have done all that stuff, launch Morrowind, click Data Files, and check any ESP's and ESM's that you added. Overall, this process is too simple once you have done it.