You can find instructions on how to use it in the topic post of this thread. As for the packed/unpacked files, with the unpacked files, depending on your machine, the game will take a very long time to start with unpacked files. On my more powerful desktop it's 10 minutes for the first launch after boot (a bit faster if I have to restart the mod again later), on my laptop about 20 minutes. Both using an SSD. But it also causes the game to require less memory space for holding the files, which means the 4GB limit (after which crashes are very common) is reached significantly later.