unable to access game key

Hi

I used the Key my friend gave me on steam to install POE 2 from there it says I do not have access to the game when it loads up. Another friend said I need to link my account with my steam account on this website which I have did but that does not seem to have worked.

I am a bit confused on how this works, have I just screwed up and not put the key in this website first like some Youtube videos have said?

Thanks for the help in advance