Stereo system as computer speakers

[demonnn]

I have a pretty old jvc HX-GD8 550watt and it has aux , so where do i go from here? I looked up on google and they are all different , I am confused ....

 

[demonnn]

my stereo has only one AUX

so I basically need one of these?
http/www.newegg.com/Product/Product.aspx?Item=N82E16882781005
3.5 to 3.5 aux cable???

my stereo does not have any rca input