nginx docker, hwo to change the public path?

I want to configure nginx with docker. My website structure is something like:

root
..controller/phpFile1.php
..controller/phpFile2.php
..controller/phpFileN.php
..public/index.php
..public/css/file.css
.. and so on

I have read various guides that recommend configurations of this type:

version: '3.6'
services:
  my-app:
    image: nginx
    restart: always
    volumes:
      - "/path/to/public:/usr/share/nginx/html"
    environment:
      # NGINX-PROXY ENVIRONMENT VARIABLES: UPDATE ME
      - VIRTUAL_HOST=your-website-one.com 
      - VIRTUAL_PORT=80
      - LETSENCRYPT_HOST=your-website-one.com 
      - LETSENCRYPT_EMAIL=your.email@domain.com
      # /END NGINX-PROXY ENVIRONMENT VARIABLES
    expose:
      - 80
networks:
  default:
    external:
      name: nginx-proxy

But.. What I should do is link the site folder inside the docker and specify the path to the public folder. How can I do it ?