Pass out a sample of a "how to" article with several paragraphs and steps to remind your students of the format. If possible, make the article about something that your students likely know how to do, such as how to make a peanut-butter-and-jelly sandwich.
Go through the handout with your students labeling the different parts of the "how to" article as an additional reminder of the format. The parts include the title, introductory paragraph, items needed to complete the task and the steps required. A "how to" article can also include a concluding paragraph, tips and warnings.
Ask thought-provoking questions of your students that are designed to remind them of the function of a "how to" article. For example, you might ask them how each paragraph that's part of the steps should begin. The answer is with an actionable verb. You could also ask a question about what's needed in the introduction. A possible answer could be a fact that provides background on what the steps will explain.
Give your students a very simple task that takes just a few steps and ask them to write their own "how to" paragraphs to demonstrate how to complete the task. Choose something simple for the mini lesson, such as "how to sharpen a pencil." Giving a few possibilities can ensure that all the students can complete at least one of the tasks.
Allow about five minutes for the students to write the steps for the process you chose in paragraph form. At this point, collect the papers. You can use them to see how your students are doing. Once you reinforce the lesson a few times with mini lessons, your students should be experts at writing "how to" paragraphs.