Go to top right of screen to 'account options' once you have logged into your account. Scroll down to 'Album settings'. Click 'Edit' option. Change 'My Album is' from Public to Private. Add your password, maybe 'ozcards'. Click save. Then you should be good to go. For the link, just copy the main page of your bucket and it will ask anyone who clicks the link for a password to enter.
I hope it works out for you