Start by finding background information on your topic. This will help you begin to understand the context of your topic (the who, what, when, where, and why), as well as the vocabulary typically used in the discipline. Context will also help you narrow the topic to a more manageable size and direct you to where to do more specific searches.
Encyclopedia-style databases (such as those listed below) offer short overviews of a topic and are good places to start.
Use these resources to find biographical information about a playwright
Use these resources to find information about a play production and the people who wrote, directed, designed, performed, and/or adapted a production
Use these resources to find primary and secondary critical commentary about how a theatrical production was received by critics and audiences
definition from: https://en.oxforddictionaries.com/definition/context
Use these resources to learn about the context around the play -- what was going on in the location in which the play was set, or during the time period in which the play was set, or about other aspects of the play