How do I connect hometheater receiver to my pc via optical

[Encall]

I try to connect my receiver to pc via optical cable but its only show 2.1 ch.
How do I make it to 5.1ch?

Receiver: Yamaha RX V363
Mainboard: H170 Gaming 3

 

[Calvin7]

Your source needs to be 5.1 ch. Something like a Blu-ray movie.

 

[Encall]

I already try running 5.1 ch video but it doesn't seem to work

 

[alan.les05]

Get a sound card with optical out ..

I got both Assus and creative, hands down Assus cards way better

Just got Assus AE 7.1 , works fantastically good on win10 .. way less driver issues than creative,.