If you've just found out about Boost.Build V2 and want to know if it will work for you, start with Chapter 3, Tutorial. You can continue with Chapter 4, Overview. When you're ready to try Boost.Build in practice, go to Chapter 2, Installation.
If you are about to use Boost.Build on your project, or already using it and have a problem, look at Chapter 4, Overview.
If you have questions, please post them to our mailing list (http://boost.org/more/mailing_lists.htm#jamboost). The mailing list is also mirrored to the newsgroup news://news.gmane.org/gmane.comp.lib.boost.build.