I am trying to understand what you mean, so if I am wrong, I am sorry. Anyways, you need to install goldeneye source to your "steam/steamapps/sourcemods" folder in order for the game to pop up in the my games list in steam. The installer should default and install to that directory, but check it during the installation to make sure that it does.
After you install the mod in that directory, be sure to go to your "tools" tab in steam and be sure that "source sdk base- Orange box" is installed (which is sounds like it is).
RESTART STEAM by closing it totally (not just in the taskbar)
Restart and you should see a game called "Goldeneye: Source Beta 4" in your my games list.
You should be good to go now. For more information about installation please refer to the wiki page below.
Good luck.
http://wiki.goldeneyesource.net/index.php/Install_Beta_3By the way Fergie, some of the installation guide needs to be updated for Beta 4 (Gamemodes and a few other things)