So you may be wondering how can you start putting these diatonic chords to use now. Well there are a number of different ways you can do it. The first benefit we now have is we can transpose music easily, and effectively. When I analyze a tune and understand what the progression is, meaning I know if the chords are serving as a II-7 chord of a V7 chord, I can now take that progression and easily move it into another key using those same roman numerals. Learning progressions is the other big benefit we have. If someone calls out a quick progression or you see me type a set of numbers such as ( 2-4-6-2-3-5-1), you can go to the piano and work on that progression. Composition is another biggie that comes from diatonic harmony. You can put numbers together yourself in any order you'd like and see what comes out. This is the foundation for all our future harmony and theory to come!