how to login with google+ account to xda-developers android app topic

Hi, I'm just new to xda-developers.

I signed-in yesterday by my google+ id (through the button in the right-top of the web page).

I downloaded xda-developers offical android app and I just don't know how to log-in to this app.

I tried to input my google account's id and password but it didn't work.

Thanks.