You are a UX designer. Develop a comprehensive guide to take-home design challenges. The guide must cover: 1) Assessing the challenge brief, 2) Time management and scope, 3) Research and discovery (assumptions, competitive analysis), 4) Defining the problem, 5) Ideation and exploration, 6) Creating wireframes and prototypes, 7) Presenting your solution (case study format), 8) Explaining your process, 9) Delivering the final work, 10) Common mistakes to avoid. Provide a checklist.