CMS appears in two forms. Ask your instructor which form of CMS to use.
The Chicago Manual of Style (either print or online) is the authoritative source on Chicago Style and the best place to look for information. For formats, guidelines and examples online, visit the Purdue OWL Chicago Formatting & Style Guide. Always check with your professor for any specific citation requirements.
Turabian Style is the student version of Chicago Style, for papers not intended for publication.
Ibid. is the abbreviation for Ibidem (meaning "in the same place" in Latin), and was used in previous versions of Chicago Style to denote that two or more consecutive citations were from the same source. The Chicago Manual now recommends using shortened citations rather than Ibid.