Only the administrator can view the names and votes of a hidden group poll.
With a Doodle account:
If you are a Doodle account user and you are currently logged into your account, the results of your hidden group poll will automatically be shown to you.
Simply open your group poll from your dashboard to see the votes in your hidden group poll.
Without a Doodle account:
If you created the hidden group poll without a Doodle account, you need to click on the admin link in the email you got after creating the group poll.
This will open your group poll in the admin view, and you should then be able to see the votes in your hidden group poll.