Each of the following sources are great places to start for getting general background information. They are written as introductions and general overviews with easy to understand prose. They each have a search bar, so you can start by searching for your topic in each of them by using keywords.
Provides a deep survey of more than 50 past and present religions practiced throughout the world. Includes thousands of primary and secondary sources that examine core beliefs, customs and practices, celebrations, key events, sacred places, and significant figures.
The Oxford Bible Commentary by 
The HarperCollins Bible Dictionary by Relevant Keywords:
Irrelevant keywords:
As defined by the Library of Congress, primary sources are the "raw materials of history." They are firsthand witnesses to the period and culture a researcher is investigating. Primary sources can be literary texts, historical accounts, personal letters, artifacts, photos, architecture, recordings, or any other text or material object that provides information about the period or culture under investigation.
Secondary sources are second-hand studies of primary sources. They are sources that interpret the meaning and significance of the "raw materials of history." In an academic context, the label "secondary source" usually means a scholarly article or book. Many journalistic sources like magazines and newspapers are also considered secondary sources. For example, you could consider Taylor Swift's Midnights album a primary source and Rolling Stone's review of that album as a secondary source. However, sometimes reseachers will use newspaper entries to study a particular period or culture. In that case, the newspaper is being used as a primary source.
Tertiary sources are in many ways a subset of secondary sources. Whereas pure secondary sources might provide more in-depth analysis and argumentation about primary sources, tertiary sources are more general overviews. They are typically reference works such as dictionary and encyclopedia entries. Tertiary sources can be further divided into two types. First, there are general tertiary sources, which are written for a general audience. These may or may not have been written by a subject-matter-expert. Second, there are discipline-specific tertiary sources. These can be more technical because they are written by a subject-matter-expert and often addressed to other subject-matter-experts. A good strategy for research is to begin with general tertiary sources and, once you have the basics, graduate to using discipline-specific tertiary sources.
