After you've clarified what you're searching for and made a list of search terms, it's time to start background research! At this point you aren't trying to do in-depth research, but instead find general information and find additional key words or fill any gaps in your knowledge. You may still have questions about your topic or haven't refined your thesis yet, but that's okay! As you search you may find more information and edit your topic or focus.
Wikipedia is a great place to start reading up on your topic, however you NEVER want to use information directly from Wikipedia! Instead, look at the bottom of a Wikipedia article and look at the sources referenced. There may be a reliable source that you can read for yourself!