You have several options! First, many students working on this assignment have found starting with the Encyclopaedia Britannica Academic database was helpful. Just type the name of a religion into the search box. Not sure what religion to pick? Take a look at the links to the Related Articles on the Religion page.
Another option is to type the name of a religion into the Library Search box on the Library's webpage. Typically, the first entry at the top of the results list will be a Research Starter article; these articles provide great summaries and overviews of topics. For example, if you do a Library Search search for Hinduism, you will get this results list. At the top of the results page, you will see a link to the Hinduism Research Starter.
The Pew Research Center has a comprehensive Global Religious Futures Project. You can browse by religion or other topics, as well as by country. The Data Explorer option lets you create custom visualizations.