The start of the pipe is where the photo shows, just after the cat. The other end just needs to exit the back of the car - you could technically stick them straight out the back if you wanted, as they're just there to let the extra noise out. But instead, put them straight into the sides of the tail pipe tips so it looks nice, as seen in the other photo
I took a video for you, just to show the underneath. As you can see they didn't do a great job of cutting cleanly through my exhaust tips, so I'm going to have to tidy that up with a dremel, but you can't see it at all unless you're under the car.
https://www.youtube.com/watch?v=q5vwJXkmul4
Skip to 0:30, that's when you hear it pop
