The Using IntelliCAD guide describes what's available in the IntelliCAD engine and details how to use IntelliCAD to draw in 2D and 3D, view drawings, dimension entities, work with layers, insert blocks and external references, add custom programs, and everything else you expect from a CAD program.
If you're investigating CAD platforms, you might find it helpful to take a look—the guides for IntelliCAD 13.1 are available for a small fee here.
ITC members receive source files and output for the IntelliCAD user guides and other documentation as part of their ITC membership. If you're an end user looking for IntelliCAD documentation, contact the ITC member where you purchased IntelliCAD.