Understanding Styles in Microsoft Word
Tips for Understanding Styles in Word by Shauna Kelly
If you spend a couple of hours learning Styles you will recover that time within the first week and be ahead of the game for the rest of your life (or at least as long as you use Word on a regular basis).
The quickest way to assign a keyboard shortcut is by right-clicking on the Ribbon and going to Customize the Ribbon, then clicking on the button at the bottom of that dialog for Keyboard Shortcuts. Pick Styles under the category, pick your Style and then assign a keyboard shortcut. I would advise saving the shortcut in the template you use for your minutes.
Templates in Microsoft Word