Use any format that makes the work understandable. If you want a structure, use this:
What I built:
Why I built it:
Hardware, models, and tools:
What runs locally and what uses the cloud:
What worked:
What failed or surprised me:
Cost, speed, or privacy tradeoff:
Next step:
Add a screenshot or short demo when it helps. You do not need a finished product. A clear experiment with honest results is enough.