DataGraph has a comprehensive set of documentation including both on-line Knowledge Base and a stand alone reference manual.
The DataGraph Manual
The DataGraph Manual is a comprehensive resource that is included in the DataGraph program.
In DataGraph, open the manual by selecting Help > Manual.
The Reference Manual is a section of the on-line Knowledge Base that contains an article for each layout setting, column type, variable type, and graphing command.
To access the Knowledge Base from DataGraph, select Help > Community Forum > Knowledge Base.
To access individual help articles from DataGraph, click the gear menu on an object and select Help. For example, here is the help link from a Plot command.
This will open your browser to the corresponding article.