For the main site I'm using J51 Serenity. I'd like to have one page show a different template. To test this I've created a new menu called Hidden Menu and a menu item and have linked my new article to it. In the Extensions>Templates I've assigned the alternative template to my hidden article but when I paste the URL into the browser bar the new article shows, but with the template for the main site (which is the J51 Serenity template). What am I doing wrong? Can you help?

The basic problem is that I'm failing to assign a template to one particular article. The default for all pages is J51 Serenity and I don't seem to be able to alter this. I've assigned a new template (which is a duplicate and edited version of the default) to one article but the system isn't respecting this and applies the default template. Can you help?