Start here:

• Customize the Ribbon (It doesn't take rocket science) by Greg Maxey, MVP
• RibbonX: Customizing the Office Ribbon by Robert Martin, Ken Puls, and Teresa Hennig
• Modifying the Quick Access Toolbar (QAT) in Microsoft Word

You do not want your customizations stored in the normal template. i have mine in a separate Global Template. It works with Word 2007-2019.