to install model packs theres stuff youre supposed to put in the models folder in you srb2's directory, wherever that is
just put whatever youre supposed to put in there like that, it's easier on a laptop for sure, but do that, and then append whatever that's in the models.dat using a text editor to wherever you want, just know that if a model is called twice the one later down the list is used instead
if you dont have a models folder or a models.dat create them.