You have to specify a volume or bind mount for you addons, for example:

volumes:
  - config:/etc/odoo
  - extra-addons:/mnt/extra-addons
  - data:/var/lib/odoo

In your /etc/odoo/odoo.conf add the following:

[options]
addons_path = /mnt/extra-addons

After this restart your container and you should be able to install custom addons. For more information you can also check out my blog post about this topic.

I hope this helps.

I already have my instance installed and configured through the terminal but I can't find the docker directories on my mac m1