I have been selected for the third scenario, and received the email. In there, there is a link ("HERE") that suposedly redeems your code and adds it to your steam library. I had previously linked to my steam account, so the only thing the link does is take me to my "rewards" G2G page. I have tried to resync and restart steam, but it won't show up in my library.

Hello @moritz121 ,

Have you clicked on the "see what you can get" button? :)

Many thanks

I did it,but nothing was added to my steam library. I'm linked with my account and my reward button now says only Free content added to yourSteam library 

Same here, nothing is added to my steam account. Why is this so difficult?!

Same here :-(

Hi! I recieved invitation and played scenario 2, now I have recieved invitation for scenario 3, but it is still locked when I open the game.. am I missing some step?

I found a solution when I clear my download cashe in setttings/download/clear the download cashe