Authentication

I've been tasked with getting our Moodle installation (3.3.3+ Build 20171338) to work with our campuses Shibboleth-based authentication. I've followed the directions in the README file and set up wverything with our identity provider and all of that is working. However, when I try the 'Test Settings'  in the 'Manage Authentication' screen I get a blank screen with 'Test Authentication settings - Shibboleth' and a Continue button. Clicking on Continue simply takes me back to the main manage authentication screen.

The link for the Shibboleteh auth does not appear on the login screen; the only way I can get it to show up is to follow the directions in step 6 of the README file for the Shibboleth Pluging:

 If you want to use Shibboleth in addition to another authentication method
    not using the integrated WAYF service from 4.b, change the 'Instructions' in
    'Administrations >> Users >> Manage authentication' to contain a link to the
     moodle/auth/shibboleth/index.php file which is protected by
     Shibboleth (see step 1.) and causes the Shibboleth login procedure to start.

And then what happens is it only shws up under a heading "Never been here? Use this link to log in and set up your account", which is not what I want to have happen. I want the students to always use our Webauth service via Shibboleth.