These terms are interchangeable for all practical purposes. The IB refer to the term bibliography in the Extended Essay Guide.
You should only include sources you have used/cited in your essay.
The reference list or bibliography is given in one alphabetical order, arranged by the surname or family name of the author. Don't forget that an organization can also be an author.
You can get further information on how to order different types of resources from the websites listed on the front of this libguide. Also in the book Cite them right.
The online citation service, EasyBib, also has an option for citing with the Harvard Style. Information about accessing the College's subscription link to EasyBib is available at the beginning of this libguide.
Remember that you're responsible for checking your work, including that in-text citations and references are correct.