When I go to Admin/Structure/Pages, the following error occurs:
InvalidArgumentException: The internal path component 'https://dssm.vegas/civicrm/contribute/transact' is external. You are not allowed to specify an external URL together with internal:/. in Drupal\Core\Url::fromInternalUri() (line 420 of core/lib/Drupal/Core/Url.php).
I either need assistance in removing the error or instruction as to where I can delete the latest page I tried to add to the site without this interface.
SELECT MAX(nid) FROM node;
to get the ID of the page you added most recently. If you then go to yoursite.com/node/ID/edit it will open the page in the page editor, and a delete link will be available at the bottom of the form.