Drag it into the hierarchy in your test scene. Right click -> Prefab -> Unpack completely.
Then you can take any individual piece and do what you will with it. When you're done just drag the individual object into your Prefabs folder for future use.
These look awesome! Going to try and use them in my PSX-visual inspired game. I love that you included some handy tutorials on how to best modify them.
If I have questions would email be the best way to contact you ?