Alright so you download the game and the mod (dev branch works for me at the current version (09bj))
Unpack both of them
Go into the unpacked
mod folder and into ccmod_resources.
Open the java decrypter > File > Open, Go to the game folder of Karryn's Prison and click "Choose Directory"
Now "Decrypt" > "All files" and wait until everything is decrypted
A new folder called "Output" should now exist inside ccmod_resources, copy it's contents into the game folder.
Lastly copy the contents of mod folder> ccmod_rescources> dev into the game folder, if you get asked to overwrite a few files you did everything right
Now start the game once to see if it crashes on startup or not, if not all should be good. Now to modify the mod go to Karryn's Prison v.9B EN\www\mods and open the file called CC_Config.js with Notepad++ (or some other program)
Note: I made this guide out of memory, but it should give you an idea how to install the mod.
Note 2: If someone is gonna read this in 6+ months some info might be outdated. Just read the install how to