The layout is slightly different now so when you want to create a new thread you first need to visit the correct section (Discussion Strategy FAQs Suggestions or Bug Report)
Once you're in the correct section click "Create Thread" which will bring you to the below image.
When creating a new thread there's a drop-down menu between "POST NEW THREAD" and the title textbox. Click that menu and select the appropriate game to post under.
Now when you click "CONFIRM" the thread will be displayed under the correct game.