Instructions:

Unzip the skin-pack of your choosing in .../Journey/Data.
It will replace files in two folders: Wads and Textures/bin.

The mod overwrites the highest tier white robe only.
Install one at any time, else they'll just overwrite one another.
Remember to backup your files first.

If there are bugs let me know: reddit.com/u/nafeij

Have fun ;)