Causes of WW1- introduction and conclusion?

Causes of WW1- introduction and conclusion?
My homework is to write an essay on this question: Was the assassination of Franz Ferdinand the most important cause of world war one? I’m not trying to cheat or anything- I just need some help. What kinds of things should I write about? I’m stuck because it needs to be about 2000 words. Also, how shall I write my introduction and conclusion? I can never write essay introductions and conclusions. Please give me some ideas. Thanks 🙂

Alliances between the major powers. The assassination was simply the tipping point. One government would jump in, then it’s allies or enemies would jump in, then THEIR allies/enemies, etc. Like dominoes. Also, there were major governmental changes in Europe several decades before (monarchies being replaced as a form of government) that led to instability, and a desire to use wars as a distraction by governments in power.
Also, imperialism, the desire to conquer played a role in some leaders minds