If I may recommend a book that greatly helped me through my undergrad - Mary Lynn Rampolla's A Pocket Guide To Writing in History. There are plenty of different ways you could write an historical essay but, on the most basic level, what you want to do is craft an argument. Historical facts and their relevancy hinge on an interpretation, because causation and significance cannot be proven in history (and these things are often in dispute), so you have to argue why your interpretation is correct

Based on your question, I am going to assume you are getting your feet wet in the history department of your college or some similar situation. If so, welcome! In any case, Rampolla's Pocket Guide as mentioned in an earlier comment is an excellent resource and very short while giving you the basic look and feel of an essay. Your general "introduction body conclusion" system from other courses or High School is broadly correct (I can't say for sure without knowing your situation a bit better) but does vary. My addition here is I recommend you make an outline. The "top" is your introduction, the big argument you are making. The "body" then breaks your arguemnt into a couple sub-points that support that argument with sources and analysis, which all gets wrapped up with a bow in the conclusion. If your professor has given different instructions or expectations, follow them. This paper should be one story or argument that some random classmate can read and follow your train of thought, outlines help keep that straight while writing.

The other thing I would add is that, depending on your course expectations, you should take some time and be sure to integrate your sources to neatly fit within the "story" you are telling. Primary or secondary, be sure to introduce and describe these sources in the paragraph they are being used in, especially if they are a major lynchpin for your essay. Don't just drop a quote into a paragraph! Sources and evidence are the bulk of your paper, but the paper shouldn't be a big collection of quotes. Analyse them and put them into the story you are telling in your paper, make them your own. If you pick up Rampolla's book, look at Chapter 6 for details on avoiding plagarism, and Chapter 7 for using sources well.

Happy writing!

EDITED for grammar.

This depends very much on the specifics of the assignment, and I strongly suggest you take this question to your teacher, professor, or TA, because they are ultimately the one you need to please. With that proviso I'll tell you what I look for from a student and some common mistakes, with less attention to a strict structure.

At the top I want a road map to your paper. I want to know what your problem is, what your conclusion is, and how you are going to get there. If you're set on a 5 paragraph structure I want your first paragraph to tell me what's in paragraphs 2, 3, 4, and 5. I want the problem and your conclusion, and the steps of your argument to reach your conclusion. If there's a debate in secondary sources that needs describing, this is where I expect to see it mentioned first.

When I was grading papers, I told students that this introduction should probably be the last bit of the paper they edit, because it's hard to do the work I want to see there if they hadn't done the rest of the paper. It's a sort of cheat: if you tell your reader what your paper is going to do, they can't bring their own expectations to it very easily unless you depart drastically from the assignment.

After that introduction is done, the rest of the paper is easy to read. I expect historical claims to be backed up by citation, with direct quotes where appropriate; I do not want your opinions aside from historical conclusions. If you said you were going to address things 1, 2, and 3 in the introduction, I expect to see those things addressed in full. And I expect your conclusion to recap your argument.

The common mistakes:

I don't need a hook. If you're working with an assigned topic, you're not writing for a general audience. You're writing for an audience that is already interested in your assignment, otherwise they would not have assigned it. I certainly don't want to see a hook that involves "the beginning of time" or "a universal truth." A lot of my students told me they were taught in high school to open an essay with a broad statement and over the course of their introduction narrow their subject down to a specific claim. Historians are historians of specific times and places. Universal claims introduce a load of assumptions that just fall apart on even a shallow inspection.

Personal opinion. Personal opinion means I want to know what you think, but it doesn't mean you can make things up. You can't tell me a story and claim it's "my personal opinion" when you get a bad grade. You can have your opinion and should show it, but it should be grounded in evidence that you provide in your text. It probably belongs in your intro and conclusion.

Quotes and paraphrases. When you give a direct quote you should tell your reader why you're quoting it and what to look for in the quoted passage. Don't leave your reader guessing at what your evidence is supposed to show. If you paraphrase, you should cite the exact passage and represent it accurately. A sloppy paraphrase might represent as the author's opinion something they are actually arguing against - a sin I am guilty of myself (don't paraphrase from memory!).

Basically, leave as few choices of interpretation of your paper open to your reader as possible, and have good evidence for everything. I do think the intro is the most important part of a strong paper in this sense. Anything more on an actual structure depends on the assignment which you haven't shared with us. Nevertheless I hope some of these comments will be useful to you.

I reckon you're a fresh university student and not someone simply asking about other's personal approaches out of curiosity, so I will mention things that might sound a bit obvious to some.

There are multiple approaches (e. g. German, Anglosaxon, French schools...), so it largely depends on what you adhere to. In Europe, Umberto Eco's How to Write a Thesis – pretty much freely availible on the internet – is universally accepted as a guide that you can always follow within humanities/social sciences. The way I personally do it:

Preparation

1. Come up with a main research question
2. Come up with a hypothesis that could be used to answer it
3. Work with primary and secondary sources to to reject or confirm the hypothesis (in historiography there is little reason to write about rejected hypotheses, so make sure your reasoning makes sense before you start writing)

Structure

1. Write a short chapter explaining the nature of your research question, providing necessary historical background (only) where needed.
2. Write a chapter examining your hypothesis and especially the theoretical approach you are using to explain the phenomenon you are studying.
3. Write a varying number of chapters (depending on the topic and purpose of your essay) about the actual subject. Make sure you always explain and answer questions relevant to that chapter. Simple accounting of facts is not a historiography, that's writing an encyclopedia. Don't stray too far from your topic, make sure to use references and footnotes if you want to mention additional information not directly relevant to you research question. The order doesn't need to be chronological, you can divide the chapters by topics, models etc.
4. After finishing writing the content of your essay, write a conclusion that summarises your findings and basically all that was done. Here avoid suddenly raising new questions that would sound like they should have been included in your work in the first place, but you can suggest what kind of further research could follow.
5. Finally write an introduction. Yes, it may sound unintuitive, but if you write this part first, you will 100% end up rewriting it anyway. Make sure to include all formalities required by your receiving institution. The introduction, the body and the conclusion should often repeat themselves – that's not an issue, it is actually desirable. Many people first read introductions and conclusions before deciding whether they want to spend time actually studying the work in detail and these parts should tell them everything about your theoretical approaches, your work methods, your findings and such.

Edit: Typo

For your main body paragraphs I recommend this old technique - PEEL. P- point - what is the point or argument? E - evidence - provide quotes, data, sources of evidence to support your point. E - explanation - explain how the evidence supports your point L - link - back to your overall argument, thesis or hypothesis.