How shall I download skin mods in GTA VC?

Hi, I have found a skin pack and downloaded it to my Mac, but I cant figure out how i get them in my Gta Vice City? And I have tried to follow the usual instructions (copy and then paste your skins into the gta vc folder) but it dont work?! All there are when I open the game folder, is a: Manual - The game itself (I cant copy/past things in that because it isen´t a folder) - And my skins folder. So how does I get the skins into my Gta VC game, and please say it in "non-computerish" language, or at least simplified. On advance thank you for your help!