get steam first and register the game on steam then when ever you play there may be an icon on your desktop or you go into steam and click play the multiplayer version from there.
My bad for a delayed comment anyway. Steam is the company that distributes online networks for the games such as counterstrike. They also sell games online allowing multilayer playing to people worldwide. Steam allows counter strike to go online or "multiplayer". You'll need that to play online, download it at the website http://store.steampowered.com/ . If you still need further help there are FAQs and instructions on the web page.
first go to google.com n then type counter strike condition zero servers n copy ip address n then open ur game n open console n type connect ip addressand enjoy the game thank u