Dependencys and Dockerfile

I have an app that i want to use with docker. As far as i know docker needs all the dependencies to work but in this case i am not sure which information Docker so i can work with the app.

It is a App we start with an LINUX Unbuntu VM right now. The manual steps we do are:
Uploading the app
Build the app on the LINUX VM
Having a demon process running the app all the time (restarting it when neccessary)
Configuring and Setting up NGINX on that VM to tunnel that app to a speficic adress.

What part of this setup do i have to put into the dockerfile?
Is the whole nginx setup neccessary in the file or do i have to do that outside of the Docker Container System?

here is an example for dotNET.

please take a look.

also please check out nginx here How to Use the NGINX Docker Official Image | Docker