It depends on which kit you purchased, you may have gotten an AMP and speakers.
Amp Connections: The power cable for the Amp could either be a black/red or black/white combination for the +12v. The Phono to RCA cable isn’t included.
Mount your Amp board to your cabinet. Connect the +12v stripped
wires end into the Power Supply.
a. Red Wire or Black with White line to +12v ; b. Black Wire to GND