Need help understanding misago-docker apps

Thanks for this software! I followed all instructions to install in a digitalocean droplet & it worked perfect.

Now I’m trying to understand how it works. After opening a bash terminal inside the misago_docker_misago running container, I can’t find the apps (misago.users, misago.core, etc).

Maybe this explanation in another thread (misago-project.org/t/add-features-to-misago/925/) is relevant :
“ Docker setup is done in a way to make it easy to deploy Misago and protect site owners from it's complexity. ;)
“ The trick to run custom Misago with misago-docker is to upload customized misago directory (the one with init.py and other python files) to directory containing manage.py. You may also need to run docker-compose build to rebuild the containers, but I don't think that's required.”

But due to my inexperience, I still don’t understand. Have looked in almost every folder but can’t find the apps mentioned in settings INSTALLED_APPS.

So, a search inside the container gave this output :

root@ad1f7f36b314:/misago# find / misago/ | grep misago | grep users | grep urls
/usr/local/lib/python3.7/site-packages/misago/users/urls
/usr/local/lib/python3.7/site-packages/misago/users/urls/api.py
/usr/local/lib/python3.7/site-packages/misago/users/urls/pycache
/usr/local/lib/python3.7/site-packages/misago/users/urls/pycache/init.cpython-37.pyc
/usr/local/lib/python3.7/site-packages/misago/users/urls/pycache/api.cpython-37.pyc
/usr/local/lib/python3.7/site-packages/misago/users/urls/init.py
find: ‘misago/’: No such file or directory
root@ad1f7f36b314:/misago#

I guess misago is been installed as a 3rd party package.

If that's the case, then my next question is :
Should I create new apps with manage.py or installed also as 3rd party package?

Thanks!. Will try that.