The first thing to check is whether the amp actually works, remove the wire you connected to the remote connection on the amp. Now connect the remote terminal on the amp to the +12v one next to it, if the amp is good it will switch on.
The other thing to check is whether the remote wire from your headunit has 12v on it when the headunit is switched on, you'll need a meter for this as the remote lead can't supply enough current to light a test lamp.
I would think between those two you'll find the problem.