There is no DAL/CODAL documentation on how to create and manage fibers

There is a bit of info in: https://lancaster-university.github.io/microbit-docs/advanced/

But, for example, nothing to indicate how to create a new fiber.

Start by reading the existing advanced documentation at https://lancaster-university.github.io/microbit-docs/advanced/. Document how to create and manage DAL/CODAL fibers, including a concrete explanation of how to create a new fiber; the advanced documentation should provide this guidance when complete.

Written by the indexing model from the issue text.