Adding a SubWoofer to a Scion HU?

[Noloc]

I know this may sound redundant but my question is the following: How do I add a subwoofer to my Scion HU? A friend of mine gave me a Pioneer IMPP 450W enclosed subwoofer and I'd like to stick it in the back of my 4Runner. I'm not looking for a complicated system. Just want to add an amp + this subwoofer to my existing system. Can someone please outline how I would do this. I don't have the amp yet.

Thanks !!!!!

 

[Noloc]

I'll settle for someone telling me which wire to use for the remote turn on for the amp from the radio harness of the standard 6 speaker radio for the 4Runner PLEASE !!!