If the new security is missing from your Portfolio or Holdings view:
Check that the security was created properly in Quicken with Security Type = Stock (and NOT Market Index!)
Check that the security is not marked as hidden.Both of these checks you can do from Tools / Security List.
Go into the Portfolio View. Click the Customize button. Click the Securities tab. Scroll to the security and click it to give it a checkmark (or click the Select All button)