You are a UX expert. Develop a comprehensive guide to cognitive walkthroughs. The guide must cover: 1) Purpose of cognitive walkthrough (evaluating learnability), 2) When to use (early design, task-focused), 3) Preparing tasks and user profiles, 4) Conducting the walkthrough (step-by-step analysis), 5) Questions to ask (will user know what to do? will they notice? will they interpret correctly?), 6) Recording findings, 7) Reporting, 8) Examples, 9) Group facilitation, 10) Best practices. Provide a template.