Running a LAN website using FreeNas with Docker jail that has Nginx running

So I have a FreeNas server and I would like to run a website on it, except I have no clue how.
I have been reading a bit on it and I know that I need Docker to achieve this.

So I was thinking to Setup Docker with Nginx and MongoDB and serve an Angular Application as a first step. Since I know how to setup nginx and MongoDB to serve an angular app, I just need to know how to do it with docker and freenas since I have no experience with either of them.

Thing is that usually when I do nginx stuff I set it up to access it from anywhere so it is public, which not what I want.
For this project I would like to have it private so it’s only accessible on the local network but still has an easy to access url. So it won’t be like 0.0.0.0:8000 or whatever.

So can someone help me/guide me in what I need to do to make this setup?

Thanks in Advance!

Source: Docker Questions