How to properly link puma, nginx, unicorn for two resources?

Question

Nginx

I have one resource which is spinning on nginx and unicorn. But I want to make a separate domain under the API on the same server. For rails 5 and API tasks, Puma is recommended. Okay, but if I understand correctly, then you need to link nginx with puma. Those. requests for a specific domain go first to nginx, and from there to puma. Is this true? If so, does anyone have a manul for both of them in a bundle, i.e. nginx and puma?