Look inside your data files folder and make sure you haven't created a second data files folder within it , if so take the contents out of the second and drop them into your main data files folder.
Installing mods is very simple. The data files folder keeps the resource files the game needs to run , a mod is simply a collection of additional resources whilst your objective is to place the mod's resource files into the corresponding resource folders that the game uses.
eg If a mod includes a meshes folder then your objective is to get the contents of that folder and paste them into the meshes folder within your morrowind/data files
folder , do the same with the textures folder etc
Don't forget to activate any esp or esm files in the Morrowind launcher.
Like this , first unpack the mod using an archiving utility such as 7 zip , winrar , izarc , etc
https://www.dropbox.com/s/ocr7pzpf3ohkplf/ScreenShot001.jpg
https://www.dropbox.com/s/zcda6y7vy30dtu3/ScreenShot003.jpg
https://www.dropbox.com/s/a5qaub4aqi9nn2q/ScreenShot004.jpg
https://www.dropbox.com/s/rutzz4txc94jorf/ScreenShot002.jpg