Unable to install weapons

[HALPMEHPLZ]

so i have windows vista, i dont have CS:S, and i'm trying to download this gun

[url]http://www.garrysmod.org/downloads/?a=view&id=77727[/url]

but i dont know how and i cant find any tutorials :(

[Mu6o]

Put them in:
%systemdrive%\Steam\steamapps\STEAM NAME\garrysmod\garrysmod
IF it doesn't work just put
[url]http://www.garrysmod.org/downloads/?a=view&id=62657[/url]