Look at the amplifier and identify the amount of power it needs to operate. Most car amplifiers operate on a 12-volt system. Also identify how much current the amplifier will draw.
Locate a 120-volt to 12-volt power supply that can supply the necessary current to power the amplifier.
Connect the positive power cable from the amplifier to the positive terminal of the power supply. Connect the ground wire of the amplifier to the negative terminal of the power supply. Connect the speaker output of the receiver to the speaker input on the amplifier using RCA cables.
Connect the amplifier speaker output terminals to the corresponding speakers. The negative terminal of the speaker should be connected to the negative terminal of one of the amplifier's speaker outputs. Connect the positive terminal of the speaker to the corresponding positive terminal of the amplifier's speaker outputs. Repeat this process until all of the speakers are connected to the amplifier.
Turn the receiver and power supply on. Test the system and identify any problems.