Stereo & Electronics - Help Please

Ok I'm getting ready to wire up my cut out and I'm a noob when it comes to wiring. I was told I can run it to the fuse box but after that I'm lost. What am I going to be hooking it up to in there?

you need a switch, so you are getting power from the fuse box (if thats what youve been told). I personally would run a wire from the battery or from the positive connection on the underhood fusebox, then to a switch, then to the cutout. ground from cutout goes directly to bare metal on the car.