Firslty place the sub and amp in a postion where you like them, once you have found it mount them down so they wont go anywhere, now assuming your battery is in the engine bay run cable from the battery down the left or right side of your car and within 18inches of the battery make sure you have a inline fuse and also make sure you are running at least 4gawg cable, now when in the boot the live cable needs to go onto the connecter on the amp under live or positive or whatever, now thats done run a cable from ground/negative conector on the amp, this need to be as short as possible and run to a solid piece of metal/frame (i would advise finding a pre drilled hole and mounting it with a nut and bolt) once the hole is found make sure you rub the paint work down to metal not paint so it has better contact. now thats done you need 2 cables going to your head unit (these must be run down the other side or middle of the car do not run them with the live cable) one will be an rca connector, now plug that into the input plug on the amp and the subwoofer output plug at the back of your head unit or if it only has one output put it in there, now the second cable is usally blue it will be blue on your headunit, its just a signal cable telling your amp that the headunit is switched on, it doesnt need to be thick cable as its only sending a signal. now last job is to run the + & - to your sub box pretty simple go to either of the channels on your amp if you have a bridgable amp but + in one channle and - in the other, now your all done you can power up, just make sure you have a quick read over how to tune the amp so it doesnt blow your sub, nothing difficult

Hope this makes sense and helps