Its no secret. I'm sure many of us had to figure out by looking at what other mods did (thats how I figured it out). Extract the meshes, textures and materials of whatever it is you want to edit. You'll have to make new files so just copy and rename them to your new armor name, try to have the mesh/texture/material names correspond. Open materials with Material Editor.exe and change the diffuse texture to your newly named texture. Open Nifscope and find where the old diffuse texture is reference and also find where the materials are referenced and then change the path to correspond with the new ones you created. Then open Fo4Editor and copy new records into a new esp file based on the original armor this is derived from. Then make sure you create an Armor Addon record and make sure it has the proper Male/Female models. Make your Armor record reference your new Armor Addon records. Now you're done and it can be used in game via console command. But wait, you want it to be available at vendors and spawn on enemies? Now you have to go and make Leveled Lists. You gotta find things that pertain to your armor mod and insert your new armor mod into lists via override files in your esp. I realize that some of you probably have no idea what I'm talking about. Thats why use this as a reference and download someones mod that adds standalone items and then just check what they did.