An idea web is just a different way to visualize your paper outline. To turn a web into an outline, you will need to put the middle of the web into a question, and that is your thesis question. The spokes outside of that question are usually your answers to that question (thesis answers). If you are making a roadmap thesis, you will combine these into one sentence which answers the thesis question. Your body paragraphs will each start with the answer in one of the thesis answers. The ideas coming off of each thesis answer should provide the detail and reasons for believing that point. For more information, see my two articles about "How to Write a Great Thesis Sentence" and "Writing Good Topic Sentences."