OK Chu, bear in mind that I am no techie, but I'll try to make this as clear as possible.
1. File Planet (The Summit) does not actually require a subscription, be really careful about scrolling through all of the pages. They just like to make you think you need a subscription. All you need to do is register, and you are fine.
2. I find the easiest way to install mods is manually.
Create a folder on your desktop, and name it according to the mod. Unzip all of the files into your folder. You may need Zip Genius (
http://www.zipgenius.it/) to unpack the files. It is unpacks a wide range of packaging formats, it's free, and it works very well.
3. Now that you have the mod unpacked, what you need to do is copy the plug-in itself (looks like a little swiss army knife or a scrap of note paper), along with any folders marked "Icons," "sounds" "textures," "meshes," music," etc.
4. Once you have hit copy ( I find it easiest to copy any folders etc. all at once), Go to you main Morrowind directory, and then to a folder named "Data Files." Open it.
5. Hit paste. You will be told that x,y, and z names already exist, agree to replacing all.
6. Fire up your game, go to "data files" from your game menu, and put a checkmark next to your mod or mods.
7. That's it, you are ready to roll.
Note 1: It is extremely important to read the readmes that come with the mods.
Note 2: Some mods conflict with one another, be sure that those you select do not do so.
Note 3: *Always* back up your Data Files folder and save games
before installing any mods, especially the large ones.