Help me i need some guidance?

The UN should be the easiest. You can Google it and read the Wikipedia entry for it to get started. It will have links to other sites at the end and you can read those. Then you can also read their website which should be listed on Wikipedia too. Then you can break you report into three sections. The formation of the body of the UN including location choice, structure and early history. Second the past 40 or so years of noteworthy historical contributions of the UN and third its current or more recent activity and maybe some thoughts on its future role in world politics.