If you want to create a Contails Account, using your Facebook account, you have to click Sign in link on Contails mainpage.

Then you have to choose Google button on the left.

On the next screen you have to enter your Google login and password and click Sign in button.

Next step is to allow Contails to receive some informations from your Google account. To proceed click Allow button.

After that you will be redirected to your new Contails account.