Ignore, for now, the Quick Styles Gallery. Click on the Styles pane launcher in the bottom right corner of the Styles group.

Then click on options at the bottom right of the pane. Choose to display all styles and in alphabetical order.

If you want to be sure that a style is in your template, put some text in the template and format it using that style.

Understanding Styles in Microsoft Word
Templates in Microsoft Word
How to control the Quick Styles gallery on the Home tab in Word