More or less, I'm trying to add in the blood fountain from the campaign into the melee maps. That I'm able to do easily enough. The problem is getting it to work how I want it to.
Basically, I want it built by a fel orc peon (again, I can do this without any difficulty) and once it's built, turns all available orc units into their fel orc counterpart. That's the part I can't get. Once I build it, it just sits there and looks pretty. I was wondering if anyone had any kind of modding experience with warcraft 3 and if so would they be able to help me. Do I need to right a code or something? Or am I not getting the triggers right?
Any help is appreciated.

The model is just a model, it doesn't do anything on its own. The transformation has to be accomplished through fancy scripting, I think. I'm pretty sure there's a web site that is dedicated to the world editor and its various functions, I think you will have much better luck accomplishing what you want if you search there. You can also try to download a map that has the feature you are looking for, and then try to replicate whatever scripts and stuff the author did. I did that a few times when I wanted to add more available races to choose from, not just swap models on existing races.

Now, if you want to swap all the orc models to the fel orc models (in the world editor), that's easier, I've done it before and it is pretty fun. You just change all the models and icons, easy-peasy. I don't know them off the top of my head, but I bet there is a site that lists the icons and models that you can dig up from the game's files that are from earlier versions of WCIII. In other words, the dev's left some of their prototype models and icons on the WCIII disc files and, if you know the right names, you can manually access them (they aren't available on the drop-down list). Also, you can probably download icons and models in case you can't find them in your files anywhere; it is possible that patches to the world editor removed access to those hidden models and icons.

Ah damn. Was afraid of that. I guess I can settle for that swap out textures suggestion.
Thinking I could also have the town hall produce fel orc peons on their own and have them as a separate building unit, giving me access to the fel orc buildings. From there I could just drop the blood fountain in that and use the fountain to produce orc units.
Not exactly what I wanted and a bit overly complicated but it'd accomplish what I want. Kinda. Well thanks anyway.

Alright. Now I've run into another problem. Specifically, getting a custom spell into the actual game. For starters, I've been pulling my hair out trying to get this ability into the game.
http://www.hiveworkshop.com/forums/spells-569/soul-grasp-v1-6-a-191024/
I've read the tutorials and they don't make any sense to me. If someone could give me step by step instructions it'd be greatly appreciated.