You've picked a topic and found your sources. Now it's time to start writing.
Write an outline of your topic in the form of a standard Wikipedia article's "lead section." Write it in your sandbox.
A "lead" section is not a traditional introduction. It should summarize, very briefly, what the rest of the article will say in detail. The first paragraph should include important, broad facts about the subject. A good example is Ada Lovelace. See Editing Wikipedia page 9 for more ideas.