buff model?
though with modelling, I'd start by downloading the necessary programs which are:
http://www.hiveworkshop.com/forums/tools-560/w3-vertexmodify-62928/
- Lets you edit (read: edit) already existing models (though you can download primitives and get busy with the Extrude tool), attach models to skeletons (not sure if limited to wc3 mpq), and UV map.
http://www.hiveworkshop.com/forums/tools.php?id=yzpnex
- converts files (or models...) from mdl. format to mdx. format, works both ways.
http://www.hiveworkshop.com/forums/tools.php?id=s5yian
- this one here is very valuable, lets you create special effects, export(so you can edit them)/view already existing models, and much else that i don't remember right now.
http://www.hiveworkshop.com/forums/tools-560/warcraft-iii-viewer-62878/
- same as model editor (minus the special effects making, and other features i never looked at) except you can convert texture files
or instead of vertex modifier, get a modelling program so you can start from scratch, though be warned, they cost money if you aquire them legally (wink wink, hint hint)
aside from that, just model weapons until you're good enough to move on.
...
You probably lost me when I said "primitives" so you'll have to look up all these definitions to learn how to model.