This How To only applies if you have not configured comments to auto-publish. This is controlled by the "post comments without approval" permission. You can set this through roles and permissions. Generally, if you want to restrict posting of comments, the anonymous user has the "post comments without approval" permission unchecked.

To approve and publish comments, visit the comment approval queue:

Click on 'administer'

1. Click administer » comments » approval queue tab.
2. For the comment you want to publish, click on the "edit" button
3. Under "Status" make sure "Published" is enabled
4. Click on "Submit"
5. Repeat steps 2-4 for each comment you intend to publish.

You can also delete comments (comment spam, inappropriate comments, etc.) by hitting delete instead of edit.