To create a LOTC template, please open the Theme Changer extension via the Tools menu -> Add-ons -> Theme Changer.
LOTC - Main Dialog
Then click "Create New Theme" so that the dialog window opens as shown below.
LOTC - Create New Theme Dialog
Complete the fields in the dialog. At the bottom is the location where your new theme will be saved. Click Create when finished. At the location that you specify, a theme directory will appear with the name that you specify.