(bcae1.com) "Battery, Ground and Remote Connections: Virtually all amplifiers have battery, ground and remote connections which must be connected for the amp to operate. The battery connection is the high current +B source that's connected to the battery via a properly fused wire. The size of the power wire is determined by the current the amplifier draws and the length of the wire (from the battery to the amplifier). The ground is another high current connection and is connected to the chassis (body/floor pan) of the vehicle. The ground wire is typically as large as the power wire. The remote connection is a low current control input that tells the power supply of the amplifier to power up."
Other than that you just connect your rca cables from the hu output to the amp input and of course the speaker cables from the amps speaker outputs to each speaker.