To Install:

Go to C:\Users\UserName\AppData\Local\Fallout4\
Right Click Plugins, Go to Properties
Turn off Read-Only
Open it, Add HDCamo.esp at the end, and Save the file
Now again right click, go to properties, and re-check read-only.

Go to: C:\Users\UserName\Documents\My Games\Fallout4\
Open Fallout4.ini
Scroll down to [Archive]
Find: sResourceDataDirsFinal=STRINGS\,
Change it to: sResourceDataDirsFinal=STRINGS\, TEXTURES\, MATERIALS\,
Save

Go To Your Fallout4 Main Directory
Open Fallout4_Default.ini
Scroll down to [Archive]
Find: sResourceDataDirsFinal=STRINGS\,
Change it to: sResourceDataDirsFinal=STRINGS\, TEXTURES\, MATERIALS\,
Save

Extract the contents to your Fallout4\Data directory.
To replace with a different paint, simply extract and replace.