What happens when downloading from game stop?

Hey i have a gamestop gift card and want to use it for a pc download game (cs go) and was wondering how tht really works.  Do they give me a steam key or something?

Some body plz!?

it takes a bit more that 45 minutes for a reply

its not a steam download, its gamestop what'd you expect

http://www.gamestop.com/gs/popups/downloads_about.aspx