This is a test of commonsense. Complete the next sentence:

How to find a phd advisor
Identify what you intend to research.
Ideally, you will have a specific idea, notion, or proposal ready for research before you find a phd advisor. Use this research topic to guide you when selecting an advisor.
If you are interested in french military history and you apply to study with a historian specializing in chinese literature, you will probably not be accepted as a student. Even if you are accepted, your advisor will be of little use in your phd career because they will not have the background you need to investigate and think carefully about the topic you're interested in.