From the pictures above, I see you've created LinkedIn and Twitter applications and added them to the Configuration area of JFBConnect. What you need to do now is actually authenticate on your site with those accounts. To do that, enable the SCLogin module and use the LinkedIn or Twitter login buttons. Once you do that, JFBConnect will recognize those users and give you the option to select them as the owner of the channel you wish to create. You need to authenticate so that JFBConnect can have permissions to behave as that user to read and/or post to the feeds for that user.
If you haven't already, please make sure to go over the
Social Channel setup guide
which will hopefully explain further.
Thanks,
Alex