Unless you are very familiar with your topic it is a good idea to get background information first. Books often provide this so a search in UC Library Search can be worthwhile. As your knowledge expands you can search for journal articles, primary sources, data and so forth.
CQ Researcher Plus Archive. Good place to start. In-depth coverage of research topics with source notes and suggestions for additional reading. Includes entries on Arms Control and Disarmament, Arms Sales and Trafficking, Ethics in War, Gun Control, Holocaust and Antisemitism, Israel Palestine and Middle East Peace, Missile Defense, Racism and Hate, Terrorism, and more.
Content Warning - some readers may find these books and reviews emotionally upsetting.