Looking for an activation key for free, thanks

[[ Serj ]]

Hi, i have downloaded steam and dota bue i cannot play it... i have only the spectator mode, i can only watch and not play, steam says me that I have already DOta and i can only buy it for a friend, but this is so wierd, cause during the installation it never asked me the activation code or the beta key... nothing, and I don't know where to type my activation code or beta key when finally some gives me one :'( damn someone help, i wanna play so bad Dota2