Edit a template

I need to add a customised form to a particular page. What's the procedure to add a template variation? Also - I seem to be able to view only the first 20 or so posts here - all the others are greyed out <??>. Many thanks, Adam. EDIT: Arrrgh! I was looking in the wrong panel (Catch Responsive Options) when I should have been looking in the "Page Attributes" panel. The greyed out posts in this forum still persists though.