The fact someone's figured out mesh replacers before nifskope or outfit studio is amazing. This Mod is simply amazing. My only issue is the gray bits on the stormtrooper armor is supposed to be black. No worries I fixed it. Assuming this is a port and not the authors own custom made assets I feel like this mod is fine. At least as fine as the original mod.

Installation
First download the Galactic Civil War Mod and follow its install instructions. That part should be obvious. 

If you haven't figured it out by now Todd decided to be silly and make your GAME Folder where you put texture and mesh replacement mods instead of the data folder in your games directory like its was for older bethesda games. Why? Beats the fuck outa me!

But there you have it just put these textures in your games folder which should look like this "Documents\My Games\Starfield" and let them overwrite the original mods textures.