Here are a few resources that will help you get started:
Primary Sources, Secondary, and Tertiary Sources
What’s the difference?
A Primary Source is original research, the first place a researcher publishes his or her findings.
Examples: journal articles, conference presentations, technical reports, field data.
A Secondary Source discusses, explains, describes, analyzes, or summarizes primary sources.
Examples :books and review articles.
A Tertiary Source describes or analyzes a group of secondary sources.
Examples: annotated bibliographies, encyclopedias and dictionaries.