How to use the DyeEditor
Load the _0 nif model if there are two models
Select the NiTriShape on the left you are applying the masks to (diffuse texture shown at bottom)
Insert layers to the NiTrishape (Ins or Add Layers button, Del will remove) add two or more
Double click the layer paths (you can leave layer 1 texture) change them to your tintmask paths
Double click the color on the mask layer (To set a default color, use alpha 0 if no default color)
Click Apply Layers
When finished, Press Ctrl+C
Save the nif
Load the _1 nif (if there is one)
Select the same NiTriShape as before
Press Ctrl+V
Apply Layers
Save the _1 nif