What is a synthesis essay and how do I write one?

What is a synthesis essay and how do I write one?
I have to type a 6 page synthesis essay for my non western lit class. The problem is I’ve never written a synthesis essay before and I’m not sure how to write it. It says in the syllabus that we have to pick a topic which I choose war ( the essay is about African literature) and choose 3 stories and a poem which the main story is about warfare. At first I thought I just have to summarize the stories but I checked online and it said to not summarize. Please help!!!!

What generalities do the stories and poem have in common?
– is there violence?
– are children exploited?
– are families destroyed?
– is it a fair war, or is the warfare usually unjust?
– is there any mention of the quality of medical supplies for soldiers?
– are villages destroyed?
– does warfare affect education?
– are there common safety or legal issues?
– how do soldiers and civilians feel about using weapons?
– does warfare provoke fear, anger, revenge, apathy, or what?

Assuming, for example, that the stories and poem all relate to the destruction and injustice of African warfare, you could develop a thematic statement in which you argue that African warfare leads to nothing but misery and ruination.

Then you just have to find factual documents to support the theme. At the end, draw up a few conclusive statements.