i made a 3d item using autodesk 3ds max (not the armour though i plan on doing that soon) but how do i open it up in NIFskope or GIMP to texturise it? and where do i go from there?. and do you have to animate all mods, like melee weapons or armour?

you create your armor in 3d max...then you either rig it in max or blender and you also map with either max or blender. Then you export it as a nif file, you can find max nif exporters and importers online same for blender. Lol good luck...

Those Max scripts are here.
http://sourceforge.net/projects/niftools/files/max_plugins/