Forum:Template on subpages of a page

How do I create and use a template that is a subpage of the page I'm using the template on?

Page: Words similar to English taboo word

Subpage template: Heading template for Words similar to English taboo word

FYI, the Wiki concerns a constructed language.

--Koppa Dasao frelangi kazelangin na 21:03, August 24, 2010 (UTC)