My buddy gave me an old Clarion 12 disc cd changer that he had sitting around his house. It is just the box thing that usually is mounted in the trunk, or glovebox or whatever. There are no wires, no head unit...nothing.

How can I hook this thing up?

It says on the front: Clarion CDC1205 Digital Audio/Twin6 12 disc CD changer ProAudio

It only has 2 places to plug anything in. On the side it has one place that looks like you plug in a 13 pin male plug, and then there is a place next to it to plug in a single male plug.

Do I need to buy a clarion head unit? Do they even sell the wires seperate from buying an entire 12 disc setup?

 

There is no industry standard for CD changer protocol so you can't mix and match car stereo components like you can with home audio gear. You'll have to get a Clarion HU if you want to use the changer. Clarion can provide you with all the connectors you'll need.