Step zero is definitely the OTP Design Principles doc (part of the OTP distribution):

https://www.erlang.org/doc/design_principles/users_guide

There are some good texts that have more examples:

Erlang & OTP in Action - https://www.manning.com/books/erlang-and-otp-in-action

Designing for Scalability with Erlang/OTP - https://www.oreilly.com/library/view/designing-for-scalabili...

One big example of distributed Erlang is Riak:

https://github.com/basho/riak