What Forte did in his book is not a method of composition. Really it's just a means of putting a label on any combination of pitches you might happen to come across. You may know a major or minor chord when you see it, but it may take some analysis to determine whether or not you've got a 6-Z12 set or a 5-30. The book shows you how to analyse nontonal music and break it down into sets, which can be compared by their interval content.

Other theorists have used Forte's set theory to build their own compositional methods. Robert Morris' **Composition with Pitch Classes** describes one such method. Be warned though, it's heavily mathematical, and its pages are strewn with equations worthy of a calculus textbook.

I use a much simpler application of Forte's set theory. My current music is built entirely from a set called 5-29 in Forte's book. I find the harmonic consitency of using only one set gives the music a harmonic coherence analogous to the ever present triad of tonal music.