Microsoft provides great learning resources for people who want to master its products.
For example, Microsoft published a course called “Format Your Document by Using Styles”. Claiming it takes about 20 minutes to complete, it gives you a basic handle on style usage in Word. You can also print the course if you like – it’s about 14 pages long.
While the course is designed for Word on the Mac, the dialogs look much the same and the concepts are identical.
Check out Microsoft’s course here.