The reason you are having difficulty is the same reason most high school and college students have difficulty writing papers and preparing speeches/presentations... remember this for future assignments:
You shouldn’t even TRY to write until you have first done the research... You cannot write about a topic unless, and until, you have LEARNED something about the topic!
Go to your school library, or research online... and find 3-5 academically-acceptable resources. If you don’t know what “academically-acceptable” means, you need to research THAT before you begin. (Concentrate on primary resources, non-fiction and biographical books, and information obtained from “.edu” sources.)
Do AT LEAST 2 hours of research - AFTER you find your references (searching for references does not count) - for each 500 words you will be writing. Take notes as you go, especially noting the main ideas that are repeated in more than one reference.
Choose one of these main ideas, and form an outline with additional information that supports that idea.
Then...and ONLY then... begin to write.