look in the customization section of the docs. The developer section deals with extending the system, not customizing/creating templates. And be sure to read up on the basics (general) to know which is which and learn the terminology. :-)
You have two ways of creating and editing templates. Either you go directly to the /design directory and use your favorite text editor to edit the templates. Or you go to the admin site and select set-up > templates.
The template system uses a default + override mechanism, with overrides being defined in an ini (override.ini). If you don't understand that, start here