The first step to completing your literature review, is to decide what is doable for you within your given timeframe. Generally, the shorter your timeline (e.g. for a class assignment), the more refined and focused your research topic should be. If you have longer timeline (e.g. for your thesis), your research topic can be broader in scope.
If you are struggling to refine your research topic, talk to your instructor or supervisor!
Below is an example of how you might take a broader research topic and develop it into a more narrowed and refined one: