Check out the tutorials that come with the program and check out the webcast from a few months ago or maybe check out AU online (http://au.autodesk.com/sessions/) which may have a class or two on creating cross sections. Broad questions like yours usually don't get much response. After doing the tutorials and you have a specific question you may get better responses.
Are you working in Civil3D or Land Desktop? If Land Desktop you may want to try over in the other News Group.
Christopher
http://civil-3d.blogspot.com/
Civil Reminders
http://blog.civil3dreminders.com/
http://www.CivilReminders.com/
Alumni