Documentation on scaling and concurrency

Current documentation (2.0.2) does not mention how to run multiple workers beyond running a supervisor process and using a shared FD. What is the correct way to scale beyond a single daphne/worker process?

Also, there is no discussion of concurrency. How many threads are run at once? How does that get affected by sync code that, e.g. talks to the database, remote API's via blocking sockets, etc? Is the number of threads a tunable parameter?