If you are looking for the source code; register here (it is free), all the images provided by U8 service contains the minimal code of S8.
For more details on "How to use S8"; feel free to contact the U8 Team.
S8 is a way to use Smalltalk designed for this decade (2010 - 2020).
It is fruit of cycles of experiences (using Smalltalk) and reflections on how software industry has changed from y2k; and concepts emerged/endured from Smalltalking community efforts (apr/2002 - ) and of successful (and failed) attempts to build modern concepts of software production for "old" smalltalkers (experts in doing smalltalk during last +20yrs).
S8 is consistent with a vision on Smalltalk ("What is Smalltalk?").
As a tool it is usable for people with similar/compatible Point of View (POV) about Smalltalk.
It has not been any attempt nor investment in designing ways/adaptions to be usable for wider audience.
What is recommended as your next step on S8?
S8 is a derivative work of other MIT licensed sources (please read license terms).
Note that S8 modules/frameworks can add dependencies dynamically to running system.
Try to use S8 for your next project, and to develop in a social context using U8. You will see the diference instantly, while working. U8 adds a lot of frameworks and tools to make your smalltalk experience more productive and instructive.