You need raw material for your essay! That is what ershad provided here. An essay is like a campfire that needs fuel (i.e. wood).
The fuel for the fire of your essay comes from books and articles. Read 1 article, and then write one sentence about it. That is how to start. That is how to turn an article into a sentence.
You probably will feel that your sentence does not adequately convey the main idea of the article, so write another sentence to explain what you mean. Then, give an example. Add one more sentence to tell about the significance of the writer's truth, and you have a whole paragraph. That is how you can get one sentence to grow into a paragraph.