In an expository paragraph, you give information. You explain a subject, give directions, or show how something happens. In expository writing, linking words like first, second, then, and finally are usually used to help readers follow the ideas.
This paragraph, like any other, organizes itself around three parts. A topic sentence allows the reader to understand what you are writing about. The middle part of the paragraph contains supporting sentences that follow one another in a logical sequence of steps. The concluding sentence closes your subject with an emphasis on the final product or process desired by the topic.