Best way to contribute to help pages?

Hello, I'm thinking about contributing to the help pages. So a couple of questions:

are there any constraints in the markdown contributed? Looking at the generated help page source, it seems I should use:
- <h3> ### and lower?
- are links to references ok (e.g. JSON Table Schema specs)?
fork, clone, branch, pr?
is it mandatory to get it running locally, or can I contribute based on the errors issued by good tables?
is this wording adequate as replacement text for the existing help?

frictionlessdata / goodtables-web