The opening section usually addresses the main subject matter while imparting a brief idea to the readers as to why the writer (you) craves to examine the topic and why is it so significant. Given that the readers would probably be unaware or uninformed about the topic, you need to address it in a simplified manner so that they can have a good grasp of the message you are trying to convey.
Lay Out the Essence (Body)
The body is indeed the main essence of the entire essay as it sheds a broader light on the issue informing the readers about the causes or basis of the problem. In addition, the section also lay down the findings of the writer that could either be totally factual, ., statistical or self-analysed such as your personal opinions or introspections of others.
Wrap Up the Exploration (Conclusion)
The ultimate section briefly lay downs or, to be precise, reiterates the overall exploration along with a final analysis or possible solution. Keep in mind that presenting a mere précis of the essay won't do any good because its main aim is to present what you've actually learnt or comprehended from the analysis.