Serving my own media to my own lan - where do I start?

I wish to build a server to serve my own multimedia data to my own network as a personal learning project and a means to avoid the dreadful automatic assumptions commercial software tries to make with a classical music collection! My client renderers are in different buildings within the range of lan and mostly connected by copper and my data is on a NAS but available using NFS or similar means.
I believe I should start with some basic reading and would appreciate suggestions for guides and help suitable for a simple non coder!

What model NAS? Many have a build it media server if it’s enabled…

Hi Malcolm, They do on Qnap which is what I am using. It is so old it came with free Twonkyserver (later machines have paid version only,) and I have been using it for years but it is not so good for me as it has many features I do not need or seek and has been behaving oddly with some renderers.
All the tools for running my own media server are also available on NAS, phpMyAdmin, SQL server, Web server etc. but I wanted to use my server my way of learning a bit about webserver basics first. My aim is to give access to my media only within my Lan.
I may quickly get out of my depth but thought I would ask as my workstation still has plenty of capacity.
Many thanks for the reply. If you think I am re-inventing the wheel and wasting my time do say as I have no idea of the obstacles I face!