I can help you out with that. 5 paragraphs seems like a big task at first, but it's helpful to break it down. Paragraph 1 is going to be an introductory paragraph. You will need to make sure that the first sentence somehow grabs your reader's attention. Ask a question for your first sentence. Use a quote from the book. Make a bold, engaging statement. Then write 2-3 sentences that broadly summarize three ways that Harry changed throughout the book. First paragraph done.
The next three paragraphs will each focus on a different change that Harry underwent. Make one paragraph about how his confidence level is vastly different at the end of the book compared to the beginning of the book. Make another paragraph about how he views friendship. Make another paragraph about how he went from having a family that hates him to a family (Hermione, Ron, etc.) that loves and appreciates him. Or make a paragraph about how his attitude toward sorcery changed throughout the book.
Finish your essay with a concluding paragraph that briefly summarizes the previous three paragraphs and tells your reader why those changes are important to care about.