Definition of the matter plus description of some basic or main features or aspects is essentially the skeleton of an essay.
So the main task is to filter available data and settle on a handful of points that you will discuss.
NB: carefully document your data and provide references page.
You used someone else’s works, so credit them duly.
Instead, try to provide some basic definition of the matter you discuss and add some crucial details about it that creates causal, explanatory or contrasting effect.
For example, ‘a so and so disease is a disease that does this and this to patients thus confining them to bed for a long time, yet the cure for it is still to be found’.
One way that I found to ease the tremendous stress of a research project was to break it into manageable chunks for my students.
Upon introducing the topic or subject of writing we began by creating a list of everything we knew about the topic and then sorting and categorizing that list.
Most probably your essay should be no more that 3-5 pages according to your instructor’s guidelines. As you have shaped understanding of the topic and created a kind of draft, you can start writing.
Writing an expository essay is the same as writing any typical 5-paragrah essay.