With bare copper wires coming from the speakers you will need to attach/solder on RCA male connectors.
Then the male RCA plugs are plugged into two female RCA jacks from a 3.5mm (1/8") stereo plug that goes into the headphone port on the radio.
However, the radio stereo headphone port will probably not have enough power to power the speakers.
So some amplification will be needed
Here is the docking station for sirius radios.
http
/shop.siriusxm.com/xm/ctl10600/cp49750/si6676040/cl1/siriusxm_dock__play_home_kit
Note those are all male.
So if your radio is something like this;
http

/shop.siriusxm.com/xm/ctl10600/cp58820/si6462130/cl1/
you could put use the male RCA adapters on the speaker wires directly.
Summary:
1/8" stereo...