The current version of Southbeach Notation is 0.9. This has been published by BPTrends, and is the version of the notation implemented by Southbeach Modeller 3.0.
When you install Southbeach the file Notation.sbm is placed at the top level of the Southbeach documents folder. Open this file in Southbeach Modeller to explore the guide directly.
Formal specifications of Southbeach Notation are also available as PDF downloads here: