I’m studying for my History class and don’t understand how to answer this. Can you help me study?

Hey there my professor have us write a discussion forum and the requirements are

  • Compose a thoughtful answer to one of the questions.
  • Begin with a clear thesis statement (argument) that directly answers the question.
  • Next, develop TWO concrete examples drawn from TWO different assigned course materials.
  • Answers must be at least 200 words in length. Please use full sentences.
  • Please cite each of your sources using a simple parenthetical citation form, including author’s last name, abbreviated title, and page. E.g.: (Foner, GML, 486).

The question of the discussion forums is:

How did the incident at My Lai affect the way Americans perceived the war in Vietnam? Why? Explain.