How to add to my Playlist

Hi all
I’m new to Raspberry Pi and in turn anything Pi related.

I have a B+ and MusicBox up and running very easy and works well.
But I want to add songs albums from my NAS box to my playlist how can I achieve this?
I work in IT so don’t mind getting my hands dirty but I’m not a coder.
I don’t have a Linux background so go easy on me

Any help would very useful.
many thanks