Please help me!

I dont know if this is the place to put this but w/e.

I bought the game today and when i got the installer it told me to point me to where i installed the game and i did, it said "enter a valid IW4 path" I tried when it was on my desktop but that didnt work either

I dont know why but when im in the folder there is only the singleplayer version of the game. Maybe that is because i havent been on the multiplayer one? maybe i will get the rest of the files when i do? well steam says IW4 is not available right now. Please help me guys, sorry for bad english, its not my first language.

This is what it says when i try to start the singleplayer version: http://tinypic.com/r/1iy879/6

When i try to start the multiplayer one it just says "not available right now" i have tried to reboot my PC