I bought a Scoshe Universal FM modulator and am a beginner when it comes to car electronics. Can someone explain to me the process of installing an fm modulator (so that I can play music on the car stereo from my phone)? Particularly with regards to where the power and grounds from the fm modulator need to go. Also, what tool will I need (I have a soldering iron if that's needed).

Any help would be greatly appreciated. Thank you.