You may either read the entirety of Arthur Miller's "The Crucible" first, and then look over the study guide, or check the guide after reading each act of the play. However, there are no rules on how to use a study guide, so look through the notes and decide which portions are most helpful. Most study guides provide a summary of the play and descriptions of what happens in each act.
To study for an exam on "The Crucible," first make sure you know what information will be on the test. If the test only covers one act of the play, focus on preparing that portion. For a test on the entire play, make sure you read the play and identify the parts that challenge you. Use your study guide to help clarify the parts you do not understand. Review the list of main characters and make note of crucial scenes and memorable lines.
Online guides like Cliff's Notes offer study aids like practice quizzes. Use these to improve your recall and to get yourself thinking about what kinds of questions are important. Re-read the play summary to refresh your memory about the plot. Cliff's Notes provides links to specific acts and scenes in the play; use these to quickly access the sections you need extra help with.
If you are writing a paper on "The Crucible," a study guide can be a starting point. You can use lists of themes or symbols to brainstorm research ideas. Make use of the historical overview in a guide, but seek out more information to get a wider picture of the historical context. At the library, request the scholarly articles recommended in the guide. Consider asking a reference librarian for additional materials to expose yourself to a wider range of ideas.