I put a Dual Cd player in both of my Rams. You need to buy the stereo, and an installation kit and a wire harness adapter kit. I switched to a single DIN head unit hence the installation kit. With the harness adapter kit, you wire your new stereo harness to the adapter and then you just plug into your stock harness, no wire cutting needed. With both kits it took me about a half hour to install the new unit complete. BTW- the Dual unit I bought has CD, USB and an AUX port so you can play from a thumb drive or your i-phone.
I got everything from e-bay, just put in stereo installation kits in the search window. There are tons of head units you could use.