When you design a template set, you can customize a copy of the provided template set, or create your own template set. If the changes are minor, it is usually quicker to customize a copy of the default set supplied with PowerMill. If you want a different look for your setup sheets, it is better to create your own HTML templates.
This document describes how to design a template set using Notepad++. However, you can use any text editor to create template sets.