This is the official documentation for Starcounter. The main parts are:
Starcounter: a short description of what Starcounter is
Tutorial: an introduction to building Starcounter applications
Guides: explains how different Starcounter features work.
Cookbook: common solutions and patterns in Starcounter
The drop down on the left sidebar lets you choose different versions of the documentation.
Sample apps are available in the StarcounterApps repository.