What were the causes of World War II and what world institutions were established during and right after the war? Please show where you found your information to support your answer, which is known as citing your sources

What were the causes of World War II and what world institutions were established during and right after the war? Please show where you found your information to support your answer, which is known as citing your sources. Please write as the professor is asking, I am attaching required material, add references.