A template is a reusable document that contains all of the attributes of the script type that you want to write: element settings, page layout, header and footer, mores and continueds, title page, SmartType lists and macros. A number of script and TV templates are included with Final Draft.
To open a template, go to File > New from Template and choose one from the category you want. A new, untitled document of that template will open. It may or may not have text; if it does, read it to familiarize yourself with how writing that kind of script is usually done; afterwards you can delete the text by pressing the Control + A keys (Windows) or the Command + A keys (Mac) and then the Delete or Backspace key.