Provide a how-to on creating each component type

What
For each type of modular component, there should be a step-by-step description of what methods need to be implemented, etc.
Why
A clear step-by-step guide can act as a checklist, both for external contributors and internal developers.
When
As soon as the API for the component is stable
Provide reference material on how each component fits into the bigger pictureIf components should be external, provide a mechanism to publicize them