If you're looking for documentation, sorry - we ain't there yet. The original documenation for bwapi should be good enough to get started. Other than that, you can take a look at ExampleBot.
Disclaimer: The API is not yet stabilized at all. Feel free to suggest changes or provide PRs. Generally I will try to keep it close to BWAPI, but will deviate if it makes sense. Ie. errors are not stored in a global error variable, rather they are return as BWResult.
The project intends to provide a client side implementation for a BWAPI server. It cannot be used to create "module" type bots.