Wiring for Sub with Stereo setup?

[morkhans]

I've got a NAD 312 stereo amp that I'm contemplating adding a sub to. I'm just not sure what the best way to wire in the sub? Do I run 2 sets of cables from the Amp speaker terminals (1 set to sub other set to speakers) or can I run it via the sub i.e Amp terminals -> sub terminals -> speakers?

Sub looks like so:

 

[TimbaLand]

 

[croak]

 

[zer0]

 

[Doge]

 

[TimbaLand]

 

[morkhans]

 

[zer0]

 

[Doge]

 

[zer0]

 

[Doge]

 

[mahleu]

 

[Doge]

 

[morkhans]