It should extract the things into the folder though? Have you tried running it as administrator?
That part is finished. It’s taking a random variation every time; the only thing it doesn’t do is taking a random model out of a branch. You can easily fix that, or rather work around that by splitting up my_variation into my_variation_entry -> [variation_with_model_1, variation_with_model_2, ...] -> my_variation_exit - which would have the same effect. Probably.
As for “taken the same every time”… unless things have changed, I’m afraid the random number generator in lua (math.random) might still not be properly initialized (something RP fixes iirc). That means that no matter how often you start the game, it will always return the same random numbers - hence, the same variations. You can fix that by placing math.randomseed(os.time()) somewhere in your code before the citizen is spawned - in that case, pretty much anywhere in your mod would be fine. Preferably the server_init_script.