General Characteristics of AutoCad:
http://www.fbe.unsw.edu.au/Learning/AutoCAD/CADnotes/chap1.htm
Drawing Controls and Manipulations:
http://www.fbe.unsw.edu.au/Learning/AutoCAD/CADnotes/chap3.htm
Drawing and Editing Commands
http://www.fbe.unsw.edu.au/Learning/AutoCAD/CADnotes/chap4.htm
Grouping Entities in AutoCad:
http://www.fbe.unsw.edu.au/Learning/AutoCAD/CADnotes/chap5.htm
Index to AutoCad Commands:
http://www.fbe.unsw.edu.au/Learning/AutoCAD/CADnotes/index.htm