90' 240sx simple wiring question

[b.arry]

Ok so would for a jvc headunit would i hookup the red on the jvc end to the blue on the car end and then yellow to red wire with black.

and also i have 3 blue wires, Will I be able to tell which on is the power wire.

[Broadfield]

Battery RED/BLACK Accesory BLUE Ground Illumination RED/BLUE Dimmer RED/YELLOW Power Antenna BLACK/RED LF Speaker (+) BLUE/WHITE LF Speaker (-) BLUE/YELLOW RF Speaker (+) BROWN RF Speaker (-) BROWN/WHITE LR Speaker (+) RED LR Speaker (-) GREEN RR Speaker (+) BLUE RR Speaker (-) PINK