Patrick Delatour

Ok so I have a 05 TSX w/out navi I want to install without having to use loc I'm not really that good on fixing audio on cars but I was able to install my amp after like 5 hrs of searching forums and just sheer luck but now I'm stuck on how I'm supposed to get the installation everyone says tap into the rear speakers but I don't even understand how to tap into it if anyone could help me that would be greatly appreciated