Take into account that this is not a official release but that it is still under development. Then you should install the Blender Nif Plugin 2.6.0a0.dev4. Important: If you want to use a newer version of Blender, don't use version 2.76b, as the copy weights between meshes doesn't work properly.You can use the old and stable Blender version 2.49, and follow the instructions given here: Installation of Blender to install everything you need.Blender: Main tool used for creating the meshes, assigning weights and creating the UV maps.
Outfit Studio wrong possitions of the Cloth bones