NOTE: In the Chicago/Turabian style, there are actually 2 methods of citing. One is called Bibliography/Note style, covered in Chapters 16 and 17 of the Turabian manual, starting on page 144. The other is called the Author-Date style, covered in Chapters 18 and 19 of the Turabian manual. Dr. Crosby wants you to use the Bibliography/Notes method. BE CAREFUL about which examples you follow in the manual or online.
The newest editions of the Chicago and Turabian manuals state that URLs and DOIs are optional if you are citing a published source, like an article from a journal, newspaper or magazine, that you saw online. So it is really up to the professor for whom you are writing a paper. In general:
Citing an essay, chapter, or other part of a book:
Citing a part of a book that was previously published elsewhere (as primary sources often are):
If you use more than one primary source from the same edited volume, your footnote should identify the primary source, but you may list the book only once in your bibliography, like this:
Citing a journal article you got as a PDF, from a database or via interlibrary loan:
Citing a journal article you got as a PDF, from a database or via interlibrary loan, with a DOI:
Citing a newspaper article you saw online:
Citing an unsigned essay or text from a webpage:
Citing a signed essay or text from a webpage:
Citing a web page with scanned image of a document from an archive:
Citing a web page with a scanned image of an unpublished letter from an archive:
Citing a web page with an interview:
*** If you do not have a date for the interview, or the name of the interviewer, simply leave them out. Likewise, if there is no "title" to the interview (i.e. “Texan Environmental Activist Diane Wilson: Why I Refuse to go Jail”) just put the word Interview after the name of the person being interviewed.