For the documentation and other product related information please visit CS-Script Home Page.
The documentation itself can be accessed online: http://www.csscript.net/Documentation.html
Or it can also be downloaded (cs-scriptDocs.7z) form the CodePlex downloads page.
Because of the large scale of CS-Script documentation it can be a challenge to find a specific information within it. Thus the all major details about hosting the script engine in applications are described on the single page: Script Hosting Guideline
The full C# 6.0 support overview can be found here: .NET 4.6 Support.
Due to the frequent equerries about integrating Roslyn to CS-Script the topic is specifically addressed here:CS-Script and Roslyn.