Hey,
There is no "rigid" structure as such for a proposal. Although there are some sections you might want to add such as:
- Problem statement
- Proposed solution
- Comparison of different approaches (pros and cons)
- Code Conventions
- Usage
- Stretch goals
- Gist of sample code
- Rough timeline
- Time commitment
Also, you don't really need to follow this to the dot :D. These are just some suggestions, and we'll be happy to review draft proposals before the final submission.
Thanks