For more complex problems, it is necessary to divide your main question into a number of sub-questions. These sub-questions relate to aspects of your main question. Zooming in on the partial aspects makes answering your main question more manageable. All sub-questions together directly answer your main question.
Example
Main question:
What is the relationship between victimization of child sexual abuse and substance abuse in early adulthood
Possible sub-questions:
You can see that a simple-looking question can generate many sub-questions and search questions. It quickly becomes more complex than you think. If you don't have enough time or resources, try delineating your question even more or consider another topic.