Compatible 5.1 system for my Asus MB

[JonDoh]

I am moving into a new room. I have the space to set up a 5.1 system but I am having trouble figuring out what components I need and what is compatible with the output from my machine.

 

I built my PC a few years ago. It does not have a dedicated sound card but the MB does have an SPDIF port. The board is Asus Prime x370-pro

 

(From the MB manufacturer: 

• Refined Audio: Realtek ALC1220 codec provides pristine and powerful audio quality)

Can someone help me figure out what components I need to get a 5.1 system running? I would like it to sound comparable to my mid-range headphones. I am not shooting for top of the line stuff but somewhere from mid range to the 80% solution. 

 

I am looking at something like the Klipsch Reference Theater pack, but I don't know if I need an amp and/or receiver in between my PC and the speakers. 

 

I am really a full noob when it comes to audio so any info down to the wires/connections/adapters I will need is appreciated.