Okay, it will be pretty short but it's right, kill me if this already is done. If you don't have any specific folder(s) create it then. :D
For client-scheme: file: Steam\SteamApps\common\counter-strike source\cstrike\resource
For script files: Steam\SteamApps\common\counter-strike source\cstrike\scripts
For font file: WINDOWS\Fonts
Screenshot "A" shows where you should add the font.
The map is called "fonts".
Screenshot "B" shows where the clientscheme file should be added.
Screenshot "C" shows where the script files should be added.