Only have one wire out of PC and trying to hook up traditional two wires to amp then to speakers

[henrykinney]

I have a one year old fancy Dell that has one wire out to what I believe is a powered sub woofer. From there two single wires go to the speakers. I have purchased a small amp which has rca jacks in and then bare speaker wire out.
Problem is how do i connect the amp from this one wire deal?

 

[Supahos]

https://www.amazon.com/AmazonBasics-3-5mm-2-Male-Adapter-Cable/dp/B01D5H8KO2/ref=asc_df_B01D5H8KO2/?tag=hyprod-20&linkCode=df0&hvadid=167146065113&hvpos=1o1&hvnetw=g&hvrand=7844495692449359093&hvpone=&hvptwo=&hvqmt=&hvdev=m&hvdvcmdl=&hvlocint=&hvlocphy=9025835&hvtargid=pla-303037967706&psc=1

If you can go directly into the amp with this cord get this if it needs to be longer get the same thing with female rca cables and add your own rca cable (I'm sorta assuming it's a 3.5mm jack on the PC