What comes first system controller or power amp?

I am throwing together a new system for DJing. 2 Bose Panaray loudspeakers, a Panaray System Digital Controller II, and a TECHNICAL PRO LZ 2100 WATT DJ POWER AMPLIFIER. I know, went cheap on the amp right? Well now I need to get need to know the correct set up to buy the right cables. I think that from my sound card output to the controller, to the amp to speakers is correct, not sure. thoughts? I might be wrong but does the system controller go before the amplifier or after?

also any idea where I can pick up new grilles for the loudspeakers?

The system controller is before the power amp.