If you have a clear understanding of your topic, your research question, and your main ideas, you might use the formal outline as a way to start organizing your thoughts. Here's an example, which you could adapt to your own purposes:
Thesis Statement
I. Introduction
II. First Main Idea
A. first subordinate idea
1. supporting detail
2. suppointing detail
B second subordinate idea
1. supporting detail
2. supporting detail
III. Second Main Idea
A. first subordinate idea
1. supporting detail
2. supporting detail
B. second subordinate idea
1. supporting detail
2. supporting idea
IV. Conclusion